[plt-scheme] Dynamic menu-item% callback assignment?

I'm using very modular MVC to create a GUI for a program. As such,
it's not really possible to create the callbacks for menu-item%s when
the objects are created. According to the MrEd manual, this is when
callbacks are created, unfortunately.

Is there any way to assign a callback later, or do I need to work around this?

Thanks,
Greg