Logging a user out of ADFS when logging out of APM

I found the ADFS articles on DevCentral and part 4 talks about the Single Sign Out, which I will test out. But there's still another step that I haven't quite figured out yet. In addition to logging out through OWA, a user could also log out through the Sharepoint links (we're using multidomain SSO, but only Exchange uses ADFS). I need to ensure that if a user clicks logout through Sharepoint, that their ADFS cookies still get deleted. Anyone have ideas on this one?

Thanks

R