its a bit old but if you install a package called...packagesearch you can see what the new names might be.
also it should be possible to run....
apt-get install usb-modeswitch....and press tab to autocomplete packagename?
2) That is one technique
Another way is to know that your modem is a "flip-flop"....its first seen as a cd....to allow ms users to self extract the driver to configure it as a modem....and when re-started in ms becomes a modem.
In linux....its first seen as a cd...using udev rules....and you can create a udev rule to flop it to a modem.
I do not use VF but to if interested...if above fails you can study this link?
where I show purtona.net you would show vfinternet.au
3) Glenn appears to have a similar modem and a different way