I have done an install of DSL with the Alcatel USB modem. The problem in trying to share this connection is it not a PPPOE connection, this modem work almost like a standard modem in that one of the computers, usually the one the USB modem is hooked to, must dial a connection. The modem uses dial up networking even though the number is from what Iíve seen only 2 digits. So the while each computer hooked to this device can make the connection, only the computer making the connection can make use of it.
The only resolution I was able to come up with was to install the modem on a host computer (which has to remain on when any others are trying to connect) and then install a Proxy server such as ANALOGX's (www.analogx.com). It is fairly simple to setup.
If you find a way that works through the USB sharing please let me know.