How to update XBAP to latest version on client computer?

Question

I developed a XAML browser application (XBAP) that is embedded within an ASP.NET web page. I am having a problem getting the latest version of the XBAP to update on the client computer. During development, I have had to use the Mage.exe tool to clear out the application cache so that my changes will be seen when running on my local computer. Besides executing Mage.exe -cc in the command line, I have also found rundll32 dfshim CleanOnlineAppCache to work just as well.

However, I do not want to ask customers to run any commands in the command line. What will I have to do to make the XBAP automatically update on the client computer? Instead of the updated XBAP refreshing on the client computer, the previous version of the XBAP continues to run.

Update

I created a bounty on this question because I have the same issue. From what I read online, XBAPs are supposed to compare the cached version # with the version # of the one on the webserver, and download the new version if it's different. I've verified that my version numbers are different, but the cached copy is still the one that is running when I launch the XBAP.

The cached copy also comes if I launch the XBAP outside of the asp.net page, although I do get the new version if I change the url parameters.

Update #2

I've discovered that the XBAP does automatically update on XP 32-bit machines, but not on my Windows 7 64-bit machine.