Pass flashvars from Flex 3 app to Flash 9 AS2

Wasn’t sure where to post this so I’ll start here.

I have a Flex 3 app that imports preexisting Flash 9 AS2 movies. All the text fields in the Flash piece are using flashvars to pull in variables. How do I get the Flex app to pass the flashvars to my Flash piece? Obviously I didn’t create the Flex app. The Flex developer isn’t sure how to get this to work. Is it even possible?