ActiveSync not keeping email sync'd between Windows XP and..

I have a iPAQ, running PocketPC, connected to my PC, running Windows XP
Professional, through USB. When I dock the iPAQ ActiveSync 3.8
synchronizes my email, calendar, files, notes, and tasks. Throughout
the day, it continues to keep these items perfectly in sync between my
PC and iPAQ, except for my email. The email is automatically downloaded
from my PC to the iPAQ to second it arrives. However, if I move email
out of my Inbox or delete email from my Inbox, this action is not kept
in sync on the iPAQ. The only way to clean up the Inbox on the iPAQ is
to undock it, and then re-dock it. Has anyone else seen this? Does
anyone know how to get around this? I was using ActiveSync 3.7, but
downloaded the new version 3.8 thinking it would help. But, I still
having had any luck.