Domain Mapping + Quick Cache -- can't clear cache manually

Starting a new thread for this issue specifically. (Migrating from this thread)

Many WPMU users have turned to the Quick Cache plugin for its built-in multisite features. I've noticed a problem however with the "Clear Cache Manually (this blog only)" button that it installs in the upper right of the WP dashboard.

SCREENSHOT: http://cl.ly/1Z1G2R140R0v0U470720

Let's say I have a Multisite network on MySites.com with a sub-blog called blog1.MySites.com, which is mapped to blog1.com

If you click the "clear cache" button while on blog1.com/wp-admin/ the cache clears just fine. . .
BUT, if you happen to be on blog1.MySites.com/wp-admin/, it doesn't clear the cache.

This is frustrating for users who aren't able to see their changes and can't figure out why the cache isn't clearing when they click the button.

Any ideas?

I know @wpcdn suggested adding a little plugin to filter that button so it shows up for sub-blog users, and then @martythornley suggested a little mod.

Is there a way to let Quick Cache know that these two (blog1.com and blog1.MySites.com) are the same?