Just been playing around with an Novatel XU870 I picked up a while ago for use on Vodafone when I realised that is supports WCDMA 850.

So after a bit of searching around on the internet it seems to get it working with 7.2Mbs you need a firmware update.  Which can be found here:

http://www.vodafone.de/hilfe-support/technischer-support/97002_117427.html

Then if you use the Novatel Dialer instead of the Vodafone supplied one which doesn't let you setup new APN's.  The Novatel Dialer can be found here:

http://www.novatelwireless.com/index.php?option=com_content&view=article&id=220&Itemid=272

Then it dials up onto XT fine (after you setup a new APN).

Now going to do the same with my Huawei E800, will post the results of that.