Just stumbled onto this and thought it might be of help to several persosn asking about 3g / hsdpa modems and how to get it working.
We might have easier ways to do this but would likely help those having issues and needing console / temminal text help to get it started.
This is not Sabayon specific but linux in general and should be similar for several cards provided you have drivers / firmware something simethign to make it talk to linux / a os.
Maybe someone that is using one of these cards can translate it into SabayonLinux for new users etc etc.
This could cover cards below in general with a few tweaks or gentoo specific commands.
* Novatel U630
* Option Fusion
* Option Quad
* Motorola E1000
* Nokia 6680 (just don't set the speed/service - no 3gonly and 384k configs)
* Option HSDPA Card
* Novatel HSDPA Card
* Huawei Card E620
* Huawei Card E220
Hope this helps.
Edit where needed so we can make a guide / update our guides.
Thanks to Cape town lunix user groups / mybroadband.co.za for the info.