A blackberry bold 9700 can be used as a generic bluetooth modem. That is, without the use of the blackberry manager software.
The trick is to change the phone number that is dailed.
The general phone number to connect to a umts (3g) network is *99#, but in the case of blackberry it should become: *99***4#.
Using this phonenumer in combination with a generic bluetooth modem (which is available after pairing) one should be able to make successfull dailup to a 3g network, using the blackberry as a theter device.