i have had a little play with not much luck but it is late. From what i have gathered so far you need to
Pair device from the laptop.
In my network places click on properties for your 3g modem, click on sharing and enable sharing this connection on this computer
then in my bluetooth places click on my bt services and right click propeties of the network access. and in the drop down box select allow connection to lan and internet on this pc.
on the hw6915 goto settings connections , bluetooth manager and then click new, click explore a bluetooth device and select your laptop from the list.
it will list a load of services scroll down and click network connection and click finish
a shortcut on your pda will now be shown right click on it and click connect, your lappy should ping clcik on the bubble and allow access.
now, thats as far as i got and its late so it gives you a heads up and if you have no luck ill try again during work tommorrow
ps i hate bluetooth lol