mail.app, offline, BAD, mmkay?

A warning and complaint to all:Offline support in Mail.app in 10.5.1 (and 10.5.0) is a DISASTER!  Actions performed offline (filing) DO NOT get synced when you connect back up.  Further, every time you send a message it warns you that you're not connected!  I lost 2 hours of email work on the plane.  Apparently only 50% of the 40 emails I sent actually found their way out, I can't tell what is what, and who has seen whom.  It's a disaster.  DO NOT USE mail.app for offline.darn it.