Recover Exchg5.5 mailbox under Exchg2003

We were unable to migrate to exchange 2003 from exchange 5.5. Unfortunatly one users mail box was not in a pst local file. We tried load exchange 5.5 on another server and the load went Ok except we can not see the users mailbox due to the SID. Is there any third party can break the edb file open?

Thank You