That's me!!
You have just written a carbon copy of my experiences.
Have you tried the version 5 Widcomm drivers? They also don't work.
I can use the Microsoft drivers to some extent, but when I do multiple downloads on 3G (not EDGE) the connection hangs and I have to disconnect and reconnect.
Maybe try the Microsoft drivers? If you've got Windows XP, uninstall your Widcomm drivers, just plug in the Bluetooth dongle and Windows should autodetect it and install the drivers. See if that works. If you can connect to the net, start downloading say 4 files simultaneously and see if your connection hangs. Mine does within a few seconds from starting the downloads. Sigh.
EDIT: Also see this thread. Maybe reply here if you have further comments, Johan
http://www.mybroadband.co.za/vb/showthread.php?t=35872&highlight=strange+disconnects
This was before my bluetooth modem (using Widcomm drivers) stopped working completely.