12.04LTS and the Telstra 4G mobile wireless modem

[Geoffrey]

This week I received from Telstra their Sierra 4G modem for mobile
broadband which I must use in my location. Those familiar with this
modem will know that it works on 3G as well and on all bands
(850/1800/2500 MHz). There is no 4G on the Sunshine Coast, QLD.
My plan/location uses 3G and 850 MHz and I am currently usine the
original Maxon BP3-EXT modem.
When connected via USB the 4G modem detects 3G with adequate signal
strength and is ready to relay data. However I cannot get 12.04 to
connect with the modem having tried all the Plan descriptions listed by
Ubuntu. I have asked Telstra for the APN via email but have not yet had
a reply. I hope that this will help 12.04 to find the right connecting
file. Eventually I wish to use the 4G modem with a laptop PC in a true
mobile anywhere situation as well as at home.
I would appreciate advice or suggestions from members.
Thank you. 
Geoffrey Combes