Even if your data backups are on tape, it will work - HANA only deletes those backup files (data or log) that are still in the original location. If you move data backups from disk to stage, then they will not get deleted (how could HANA do this). So your problem is solved.
If you write your backups to disk anyway, you really want to check if BACKINT is an option for you, there are a lot of professional backup solutions that have implemented HANA's BACKINT interface.
Best,
Richard