theitd wrote: I've tried various fw's (3.2.1 --> 3.3.2 RC8) with a Vodafone K3520-Z - and no joy. This is the white one supplied in the last month (jul-aug 2009) from Vodafone.

I'm having the same problem usinfg the K3520 from Vodafone.
Originally used a 2800 series but Draytek said, after several emails, that the 2800 series wasn't compatible with a 3G dongle and that I should try the 2820 instead. Went a bought a 2820 to find it still doesn't work.
I've tried joelang's solution but that doesn't seem to work for me either.