Index: src/org/jboss/tools/hibernate/jpt/core/internal/context/java/HibernateJavaManyToManyMapping.java
===================================================================
--- src/org/jboss/tools/hibernate/jpt/core/internal/context/java/HibernateJavaManyToManyMapping.java	(revision 23368)
+++ src/org/jboss/tools/hibernate/jpt/core/internal/context/java/HibernateJavaManyToManyMapping.java	(working copy)
@@ -16,6 +16,7 @@
 import java.util.Vector;
 
 import org.eclipse.jdt.core.dom.CompilationUnit;
+import org.eclipse.jpt.core.JpaFactory;
 import org.eclipse.jpt.core.context.java.JavaPersistentAttribute;
 import org.eclipse.jpt.core.context.java.JavaRelationshipReference;
 import org.eclipse.jpt.core.internal.context.java.AbstractJavaManyToManyMapping;
@@ -29,6 +30,7 @@
 import org.jboss.tools.hibernate.jpt.core.internal.context.HibernatePersistenceUnit.LocalMessage;
 import org.jboss.tools.hibernate.jpt.core.internal.context.Messages;
 import org.jboss.tools.hibernate.jpt.core.internal.context.basic.Hibernate;
+import org.jboss.tools.hibernate.jpt.core.internal.jpa2.HibernateJpaFactory2_0;
 
 /**
  * @author Dmitry Geraskov
@@ -56,8 +58,8 @@
 	}
 	
 	@Override
-	protected HibernateJpaFactory getJpaFactory() {
-		return (HibernateJpaFactory) super.getJpaFactory();
+	protected JpaFactory getJpaFactory() {
+		return super.getJpaFactory();
 	}
 	
 	@Override
@@ -104,13 +106,21 @@
 		if (getForeignKey() != null) {
 			throw new IllegalStateException("foreignKey already exists"); //$NON-NLS-1$
 		}
-		this.foreignKey = getJpaFactory().buildForeignKey(this);
+		this.foreignKey = buildForeignKey();
 		ForeignKeyAnnotation foreignKeyResource = (ForeignKeyAnnotation) getResourcePersistentAttribute().addAnnotation(ForeignKeyAnnotation.ANNOTATION_NAME);
 		this.foreignKey.initialize(foreignKeyResource);
 		firePropertyChanged(FOREIGN_KEY_PROPERTY, null, this.foreignKey);
 		return this.foreignKey;
 	}
 
+	private ForeignKey buildForeignKey() {
+		if (getJpaFactory() instanceof HibernateJpaFactory)
+			return ((HibernateJpaFactory) getJpaFactory()).buildForeignKey(this);
+		if (getJpaFactory() instanceof HibernateJpaFactory2_0)
+			return ((HibernateJpaFactory2_0) getJpaFactory()).buildForeignKey(this);
+		return null;
+	}
+
 	public ForeignKey getForeignKey() {
 		return this.foreignKey;
 	}
@@ -132,7 +142,7 @@
 	}
 	
 	protected ForeignKey buildForeignKey(ForeignKeyAnnotation foreignKeyResource) {
-		ForeignKey foreignKey = getJpaFactory().buildForeignKey(this);
+		ForeignKey foreignKey = buildForeignKey();
 		foreignKey.initialize(foreignKeyResource);
 		return foreignKey;
 	}
Index: src/org/jboss/tools/hibernate/jpt/core/internal/jpa2/HibernateJpaFactory2_0.java
===================================================================
--- src/org/jboss/tools/hibernate/jpt/core/internal/jpa2/HibernateJpaFactory2_0.java	(revision 23368)
+++ src/org/jboss/tools/hibernate/jpt/core/internal/jpa2/HibernateJpaFactory2_0.java	(working copy)
@@ -16,6 +16,7 @@
 import org.eclipse.jpt.core.context.java.JavaAssociationOverride;
 import org.eclipse.jpt.core.context.java.JavaAssociationOverrideContainer;
 import org.eclipse.jpt.core.context.java.JavaAssociationOverrideRelationshipReference;
+import org.eclipse.jpt.core.context.java.JavaColumn;
 import org.eclipse.jpt.core.context.java.JavaEmbeddable;
 import org.eclipse.jpt.core.context.java.JavaJpaContextNode;
 import org.eclipse.jpt.core.context.java.JavaManyToOneMapping;
@@ -26,7 +27,9 @@
 import org.eclipse.jpt.core.context.java.JavaPersistentAttribute;
 import org.eclipse.jpt.core.context.java.JavaPersistentType;
 import org.eclipse.jpt.core.context.java.JavaSequenceGenerator;
+import org.eclipse.jpt.core.context.java.JavaBaseColumn.Owner;
 import org.eclipse.jpt.core.internal.jpa1.context.java.GenericJavaAssociationOverrideContainer;
+import org.eclipse.jpt.core.internal.jpa1.context.java.GenericJavaColumn;
 import org.eclipse.jpt.core.internal.jpa2.GenericMetamodelSynchronizer;
 import org.eclipse.jpt.core.internal.jpa2.context.java.GenericJavaAssociationOverrideRelationshipReference2_0;
 import org.eclipse.jpt.core.internal.jpa2.context.java.GenericJavaCacheable2_0;
@@ -173,5 +176,9 @@
 	public JavaOrderColumn2_0 buildJavaOrderColumn(JavaOrderable2_0 parent, JavaNamedColumn.Owner owner) {
 		return new GenericJavaOrderColumn2_0(parent, owner);
 	}
-		
+
+	@Override
+	public JavaColumn buildJavaMapKeyColumn(JavaJpaContextNode parent, Owner owner) {
+		return new GenericJavaColumn(parent, owner);
+	}
 }