recover ifolder 3.6 encrypted files?

Hi!
we have an encrypted ifolder folder to restore, but this does not work. we have a daily backup of the encrypted folder.
so we tried to restore one of the files to an workstation and then to uploades this file to the ifolder using the webclient and the windowsclient. but both of this things dod not work. the file is encrypted and not readable!
so how can i revocer files/folder from an encrypted ifolder folder.
we are using ifolder 3.6 on oes2 sles10sp1


any ideas????
thanks ahead
TS