Just to be on the safe side, you might want to add what error you're getting, It could aid in helping getting things to work right.

A couple of off handed guesses though, You might need another level of indirection (an extra $ and some curly braces perhaps) It would seem like what you're doing is creating an an indirect reference in effect. Perhaps better than trying to get past levels of indirection and such, you could pass the object itself. I think it would be achieved by passing a reference

But besides that I'll leave it to wiser monks than myself, or at least wait for an error message :)

Good Luck.