[Zope] Multiple selection properties in Zclass Propertysheets

Ok I've gotten this far: I create a lines type property in the 'Properties' tab of the product, and add a few entries to it. When creating the selection type property in the ZClasses propertysheet, I specify the lines type variable name as the value. This works insofar as now the propertysheet displays the options defined in the lines property as a dropdown form element, but it does not work correctly in the propertysheet of an instance. Am I putting the lines property in the wrong place, or is this a bug? Michael Bernstein.