diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/profilemodel/PEInstance.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/profilemodel/PEInstance.java
index 67c306062..16e154b6c 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/profilemodel/PEInstance.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/profilemodel/PEInstance.java
@@ -46,6 +46,7 @@ import org.hl7.fhir.r4.model.Extension;
 import org.hl7.fhir.r4.model.HumanName;
 import org.hl7.fhir.r4.context.IWorkerContext;
 import org.hl7.fhir.r4.model.Address;
+import org.hl7.fhir.r4.model.BackboneElement;
 import org.hl7.fhir.r4.model.PrimitiveType;
 import org.hl7.fhir.r4.model.Quantity;
 import org.hl7.fhir.r4.model.Reference;
@@ -225,6 +226,10 @@ public class PEInstance {
     return (Type) data;
   }
   
+  public BackboneElement asElement() {
+    return (BackboneElement) data;
+  }
+  
   public CodeableConcept asCodeableConcept() {
     return (CodeableConcept) asDataType();
   }
@@ -293,18 +298,27 @@ public class PEInstance {
     return builder.getContext();
   }
 
-  public void addChild(String name, Type value) {
+  public Base addChild(String name, Type value) {
       PEDefinition child = byName(definition.children(), name);
       Base b = data.setProperty(child.schemaName(), value);
-  }
-  
-  public void addChild(String name, String value) {
-    PEDefinition child = byName(definition.children(), name);
-    Base b = data.setProperty(child.schemaName(), new StringType(value));
+      return b;
   }
 
-  public void addChild(String name, Date value) {
+  public Base addChild(String name, BackboneElement value) {
+      PEDefinition child = byName(definition.children(), name);
+      Base b = data.setProperty(child.schemaName(), value);
+      return b;
+  }
+  
+  public Base addChild(String name, String value) {
+    PEDefinition child = byName(definition.children(), name);
+    Base b = data.setProperty(child.schemaName(), new StringType(value));
+    return b;
+  }
+
+  public Base addChild(String name, Date value) {
     PEDefinition child = byName(definition.children(), name);
     Base b = data.setProperty(child.schemaName(), new DateType(value));
+    return b;
   }
 }
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/PEInstance.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/PEInstance.java
index a139b1ea9..c6b726784 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/PEInstance.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/PEInstance.java
@@ -46,6 +46,7 @@ import org.hl7.fhir.r5.model.Extension;
 import org.hl7.fhir.r5.model.HumanName;
 import org.hl7.fhir.r5.context.IWorkerContext;
 import org.hl7.fhir.r5.model.Address;
+import org.hl7.fhir.r5.model.BackboneElement;
 import org.hl7.fhir.r5.model.PrimitiveType;
 import org.hl7.fhir.r5.model.Quantity;
 import org.hl7.fhir.r5.model.Reference;
@@ -225,6 +226,10 @@ public class PEInstance {
     return (DataType) data;
   }
   
+  public BackboneElement asElement() {
+    return (BackboneElement) data;
+  }
+  
   public CodeableConcept asCodeableConcept() {
     return (CodeableConcept) asDataType();
   }
@@ -293,18 +298,27 @@ public class PEInstance {
     return builder.getContext();
   }
 
-  public void addChild(String name, DataType value) {
+  public Base addChild(String name, DataType value) {
       PEDefinition child = byName(definition.children(), name);
       Base b = data.setProperty(child.schemaName(), value);
-  }
-  
-  public void addChild(String name, String value) {
-    PEDefinition child = byName(definition.children(), name);
-    Base b = data.setProperty(child.schemaName(), new StringType(value));
+      return b;
   }
 
-  public void addChild(String name, Date value) {
+  public Base addChild(String name, BackboneElement value) {
+      PEDefinition child = byName(definition.children(), name);
+      Base b = data.setProperty(child.schemaName(), value);
+      return b;
+  }
+  
+  public Base addChild(String name, String value) {
+    PEDefinition child = byName(definition.children(), name);
+    Base b = data.setProperty(child.schemaName(), new StringType(value));
+    return b;
+  }
+
+  public Base addChild(String name, Date value) {
     PEDefinition child = byName(definition.children(), name);
     Base b = data.setProperty(child.schemaName(), new DateType(value));
+    return b;
   }
 }
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/gen/PECodeGenerator.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/gen/PECodeGenerator.java
index 0855aeeb0..76629a331 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/gen/PECodeGenerator.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/profilemodel/gen/PECodeGenerator.java
@@ -252,7 +252,7 @@ public class PECodeGenerator {
               w(enums, "  public enum "+name+" {");
               for (int i = 0; i < vse.getValueset().getExpansion().getContains().size(); i++) {
                 ValueSetExpansionContainsComponent cc = vse.getValueset().getExpansion().getContains().get(i);
-                String code = Utilities.nmtokenize(cc.getCode()).toUpperCase();
+                String code = Utilities.javaTokenize(cc.getCode(), true).toUpperCase();
                 if (cc.getAbstract()) {
                   code = "_"+code;
                 }
@@ -398,7 +398,11 @@ public class PECodeGenerator {
     private void genLoad(boolean isPrim, boolean isAbstract, String name, String sname, String type, String init, String ptype, String ltype, String cname, String csname, boolean isList, boolean isFixed, PEType typeInfo, boolean isEnum) {
       if (isList) {
         w(load, "    for (PEInstance item : src.children(\""+sname+"\")) {");
-        w(load, "      "+name+".add(("+type+") item.asDataType());");
+        if ("BackboneElement".equals(type)) {
+          w(load, "      "+name+".add(("+type+") item.asElement());");          
+        } else {
+          w(load, "      "+name+".add(("+type+") item.asDataType());");
+        }
         w(load, "    }");
       } else if (isEnum) {
         w(load, "    if (src.hasChild(\""+name+"\")) {");
@@ -407,7 +411,7 @@ public class PECodeGenerator {
         } else if ("Coding".equals(typeInfo.getName())) {
           w(load, "      "+name+" = "+type+".fromCoding((Coding) src.child(\""+name+"\").asDataType());");
         } else {
-          w(load, "      "+name+" = "+type+".fromCode(src.child(\""+name+"\").asDataType()).primitiveValue());");
+          w(load, "      "+name+" = "+type+".fromCode(src.child(\""+name+"\").asDataType().primitiveValue());");
         }  
         w(load, "    }");      
       } else if (isPrim) {
@@ -424,8 +428,12 @@ public class PECodeGenerator {
         w(load, "      "+name+" = "+type+".fromSource(src.child(\""+name+"\"));");
         w(load, "    }");
       } else {
-        w(load, "    if (src.hasChild(\""+name+"\")) {");
-        w(load, "      "+name+" = ("+type+") src.child(\""+name+"\").asDataType();");
+        w(load, "    if (src.hasChild(\""+name+"\")) {");      
+        if ("BackboneElement".equals(type)) {
+          w(load, "      "+name+" = ("+type+") src.child(\""+name+"\").asElement();");
+        } else {
+          w(load, "      "+name+" = ("+type+") src.child(\""+name+"\").asDataType();");
+        }
         w(load, "    }");
       }
     }
@@ -447,7 +455,7 @@ public class PECodeGenerator {
         } else if ("Coding".equals(typeInfo.getName())) {
           w(save, "      tgt.addChild(\""+sname+"\", "+name+".toCoding());");
         } else {
-          w(save, "      tgt.addChild(\""+sname+"\", "+name+").toCode();");
+          w(save, "      tgt.addChild(\""+sname+"\", "+name+".toCode());");
         }  
         w(save, "    }");      
       } else if (isPrim) {