I have a test app that shows the problem. I tried to e-mail it to support@wptools.de and received an error:
The original message was received at Fri, 03 Dec 2004 18:04:38 -0500
----- The following addresses had permanent fatal errors -----
<support@wptools.de>
----- Transcript of session follows -----
554 permanent problems with the remote server mailin.webmailer.de