So after a lot of tries I have found the error in this doku :-)
It was described by the author Hans in a posting ( http://forums.b2evolution.net/viewtopic.php?t=724 )where he wrote:
in the CVS you can find mms.php, which enables you to send photos straight from your phone to your site. Very soon this script will also be capable to receive photos by email.
To use the current mms.php simply put the following server url in your cell phone (adapt to your own settings):
So note the part after the ? in the URL where you give Login, Pass & Topic!
After I have changed that, I’ve got it to work with T-Mobile / Austria.