Thanks for your reply jny.
Unfortunatley, I don't think there is access to an object ant the point the menu option is selected.
All i seem to have available is an ObjectID (moniker) and other limited properties shown within the "Params" function within clientMenus.js
RW
str.AppendFormat(@&pObj.custom2={0}, <IManDocument|IManWorkspace_C2_value>);