I have run Knoppix 6.0 and 6.1 trying to get a mobile broadband connection with Huawei e220.
A while after initiating the applet I get the opportunity to supply my password. When this is done (the Huawei starts blinking blue) the manager seems to continue trying to connect to the ISP. Mostly it stops after a while freezing the computer forcing me to pull the plug to get out of the situation. Sometimes, however it really does connect. In such cases everything goes OK. It is however most annoying. In a hurry it is never possible to rely on getting a connection established.
I have had the same experience with Ubuntu 9.04 and with an installation of SUSE 11.1.

I have earlier run Knoppix 5.3 and 5.31 using wvdial with Huawei e220. I have very seldom experienced any problem connecting that way.

In the Network Manager I have also tried various combinations and none of the protocols (eg. PAP, CHAP) provided.

I am grateful for any hints.

Otherwise I hope this will be fixed in future releases.