I don't think there's a way.  I did a competitive evaluation of ADSM vs
Harbor, a mainframe-based storage manager.
Harbor did have the nice feature that it could make a copy tape on the fly.
But I looked hard for a way to do that in ADSM, and at the time, there was
none. (Though using a disk storage pool gets you similar functionality,
i.e., you don't have to back the client up twice to get your copy...)