email subject line "T-Mobile SMS E-Mail"... wtf?

I have recently started to use my 6310i to send emails. It works
allright, except that each and every email I'm sending gets the subhect
line "T-Mobile SMS E-Mail".

The *real* subject line is prepended to the message bod, so what the
recipient gets, looks like this:

Subject: T-Mobile SMS E-Mail
Message: (my subject line) message text

Is there a way to get the subject line where it belongs?

I'm on T-Mobile Germany.