I've just gotten an x51v, which I love, except for some typical synching problems. Activesync was recognizing the ppc, and I could "explore" it from the desktop, but AS wouldn't get beyond saying it was "connecting" and giving me the spinning green.
I finally traced the problem to a subtle ZoneAlarm issue. I had already gone into the ZA Programs list (under the Program Control tab) and given all the activesync applications across-the-board permissions. But then I discovered I also had to change the Zone setting of the "Windows Mobile-based Device" from "Internet" to "Trusted" in the Zones list (Firewall tab). (I might also have had to cradle the ppc in order to get this line to show up in ZoneAlarm.) The problem was probably that my internet zone is set to high security, so that my PC's IP address was undetectable by the PPC until I moved the PPC to the trusted zone. But this was an entirely silent problem: neither AS nor ZA gave any indication of it.
Somewhere along the line I also upgraded to the bootleg version of ActiveSync 4.1, but that didn't seem to help or hinder.
I've also had lots of problems with Windows Firewall, so my advice, if you're having synching problems, is to rule out the firewall by disabling any that are running. And don't forget to then reboot, or at least disable and reenable the relevant Local Area Connection and then "Repair" it, which is what I had to do for the PC to fully shake off ZA's clutches.
btw, lots of good info on the following pages, although they didn't tell me what I needed to do:
http://www.pocketpcfaq.com/raj/ZA.html
http://www.pocketpcfaq.com/faqs/acti...ewallproxy.htm