Make page ads refresh on Flash click events

I have a page with a fairly detailed Flash app embedded. There are also 3 ad units on this page. I’d like to setup the swf to force the three ad units to refresh when a user navigates through to a new section of the flash app. I assumed I’d need to setup iframes around the adds, then call some js function from Flash which performs a document.location action on the iframes, and it seems to be working in Firefox, but not IE. Has anyone needed to do something similar and maybe offer some insight? Or a better less hacky solution?