After a few hours (and mistakes) I have finally made my Mint 14 network manager recognise my 4g dongle. my problem is that it connects for 5 seconds and then disconnects.

My settings are: *99# for number
: telsra.internet for APN
I've tried various others but they won't connect or drop out instantly.

All other settings seem to be automatic but can be changed.
Any help or ideas would be appreciated.