Just to clarify some of the above points.
The partial catalog recovery suggested by StefanosM would be about the only poosible way to do what you are after (with the NetBackup version you are using). Be aware though that the process does not create the tape assignments, so you need to make sure the tapes are protected from being used (NetBackup will believe them unassigned and available) - the way to do this is to place the tapes in a pool that is not used for scratch (the article mentions this). The process also would allow you to test recovery in the enw environment from tape before you commit (and decomm the old master). Nothing in the cat_export/cat_import would affect the status of the old master.
Cross OS catalog migration is possible now for customers. There are some caveats (same master server name is the main one), but this is only supported to version 10.1.0.1. The tool is called NetBackup Service Migrator and should be available to download via the download portal (under updates from memory).
The catman tool may also have been helpful for cross OS and different name migration, but again at present this is only supported to version 10.1.0.1.
The reasons for the above two is the NetBackup database change from SQLAnywhere to PostgreSQL when upgrading to 10.2 - this requires some major changes to the catman tool and the server migrator.
Cheers
David