[otrs] OTRS & PGP

Hi all, i found a problem when replying to an e-mail - while creating reply message, it's not possible to choose key for signing it. is there something i should be aware of, when using this feature? It funny beacuse when I try to create new mail in same queue, then "Sign:" options is there (?). I have OTRS 2.1.5, keyring is ok and hexId/passwords are added to SysConfig Crypt:PGP, also all keys are visible under Admin:PGP menu. Best regards, Alex