server 5 calendar invitations get strange "@mac.com"

hi,

i finally got calendar mail-invitations working with an external mail-server.

everything works fine: sending invtiatiosn and get replies (catchall-mail-account) .

everything works, but one thing: os x server seems to add "@mac.com" to

the senders name, e.g. -> "Company Name Event @mac.com".

an so all my invitations go directly to the spam-folder.

does anyone has a clue?

boris