[CipherMail User] S/MIME message has been decrypted but sending encrypted!

Hi there, my problem exists for a longer period now. As more and more S/MIME crypted mails are incoming, situation is getting annoying. So I started solving the problem, unfortunately without success. I have internal domains (locality "internal") in ciphermail, S/MIME certficates including private keys are successfully imported, mail routing works, everything is running fine except one weird thing: When S/MIME crypted mails are incoming for my user they will be decrypted by ciphermail. Logfile is showing "S/MIME message has been decrypted." and "S/MIME signature was valid", but only crypted mails are arriving in my inbox. I have searched for ages now and checked the configuration many times. Also reinstalled the server. Problem stays the same. Ciphermail does not decrypt mails. Anybody knowing this problem? Many thanks in advance. Andreas