With 3.6, docs requires that nodes provide separate help id's for 
themselves and for their property sheet.  This is accomplished 
by calling someNode.getValue("propertiesHelpID").

Is there any particular reason this can't be delegated too?  
Something like:

public Object getValue (String key) {
   Object result = super.getValue(key);
   if (result == null) {
       return original.getValue(key);
   }
}

?