I had a small bug that prevented some programs to connect to the Internet via ActiveSync (Resco Update, IM+...). So here's what I did: updated ActiveSync to 6.1 and applied the above fix for COM 1. Then it worked fine after a soft reset.
Also, it seems WM6 eats a bit more of RAM doesn't it ? Not to worry, just something like 1MB
Edit : Actually, more like 2MB
Still, much faster... so who cares