I took a quick look at the Seven website, but after several pages I still don't quite understand what the program(s) does(do). No screenshots, and only a basic explanation. It seems to be marketed more towards companies and folks looking to replace Exchange functionality. Thanks for the offer of an alternate fix, but I don't think I'm the right kind of user to test.
On the other hand, I figured out how to resolve my issue. Installing the Windows Live for Windows Mobile did the trick. It updated the Messaging system to include the HTML sync and Push technology from Live, so everything is running smoothly now. There were a few other handy apps on the page as well, including Microsoft MyPhone, which also syncs SMS, pics and a few other things from the phone, making backup of critical data (up to 200MB) incredibly easy. And of course Facebook and Netflix apps.
http://www.microsoft.com/windowsmobi...t/default.mspx
Now that I've found this (and have a better idea how to search the forums for the solution), I'm sure there is probably several pages discussing this issue already. I'll ask the mods to delete this as redundant. If not, I'll ask them to make it a sticky and post the MS link above for the several handy free apps. I bet most of the regulars are already quite familar with the page though.