I have begun using RADContainer objects to store non-visual beans in my visual 
forms.  I had to add a section of code to JavaCodeGenerator.addInitCode in 
order to actually generate the code.  It seems to work well.
However, in order to get it to save changes to the form, I had to add a small 
fix to GandalfPersistenceManager.  I have not been able to isolate the cause, 
but have found a "patch" that avoids the problem.
The problem is in the first line of the saveConstraints method in GPM:

    private void saveConstraints(~~) {
      LayoutSupport laySup = component.getParentContainer().getLayoutSupport();
      if (laySup == null) return;

When I try to save a form with RADContainer objects, 
component.getParentContainer() returns null, which breaks this line.
The fix I added simply tests component.getParentContainer():

        RADVisualContainer parent = component.getParentContainer();
        if (parent != null)
           laySup = parent.getLayoutSupport();
        if (laySup==null) return;

The result is that if component.getParentContainer90 is null or 
component.getParentContainer().getLayoutSupport is null, then return - the same 
IMHO as the original, but with added error checking.  I suggest that this bit 
of code be added, if not for RADContainer support then simply for robustness.

btw, my fix for JavaCodeGenerator.addInitCode adds the following code 
segments.  I don't think that this should not impact the persistence manager.

Added at line 661 & 681:
     } //PENDING - adding to non-visual containers
      else if (comp instanceof RADContainer)
       generateNonVisualComponentAddCode(children[i],(RADContainer)
comp,initCodeWriter); }

Added elsewhere:
    private void generateNonVisualComponentAddCode(RADComponent comp,
     RADContainer container,Writer initCodeWriter) throws IOException{
        initCodeWriter.write("\n" + container.getName());
        initCodeWriter.write("." + container.getContainerGenName()); 
        initCodeWriter.write("add(");
        initCodeWriter.write(comp.getName());
        initCodeWriter.write(");\n");
    }