[otrs] Autmatic decryption of PGP attachments?

Hi there! We're having some trouble with the otrs PGP option. At the moment we are able to receive PGP encryptet mails just fine, but if the mail has an attachment, this attachment won't be decrypted. This is very strange behaviour and since i could not find any related information on the net, i guess it's a bug? best regards, Kevin