I just upgraded from Android Revolution 3.6.8 to 3.6.13 without wiping my stuff.
The problem of HTML mails from ActiveSync with my hotmail went back to TXT and the option is grayed.
So, I just copied the mail.apk (attached to my previous post) to system\app with ES explorer on phone (overwriting the one existing there) and tried to install the apk from system\app and yes it doesn't complete the installation but the icon disappeared from menu and main screen. So, I rebooted my phone. After that my email icon came back and when I go to option, I can now select HTML or TEXT.
My Sense is 3.0, Android 2.3.4 and Android Revolution 3.6.13 with 1.72Ghz CPU.
My method is working and I confirm I did it twice !