thx for your great and hard work i have tested the TNEF implementation ...
the output is not correct ...the TNEF Libary put the responce directly via echo out
and put the response not to the return var.
the message in the error log ...
[10-Mar-2009 14:56:02] PHP Warning: Cannot modify header information - headers already sent by (output started at /var/www/htdocs/roundcube/program/lib/tnef_decoder.inc:121) in /var/www/htdocs/roundcube/program/steps/mail/get.inc on line 110
and for the incorrect output see attached image.