As previously reported, I tried the update to Android 3.2 on my Tab and was not happy about the new EMail app. At the weekend I had a little bit of time, so I tried to get the Email.apk from Android 3.1 into Android 3.2.
Long story short, I failed.
TitaniumBackup PRO was restoring or hours (the option to migrate from a different ROM version was enabled) until I killed the app, and it did not get anywhere (I just emailed their support if I did something completely stupid, or of this is a bug in TB). And a copy by hand into /system/apps did not work (app fails to start).