It's not an easy task, unless you are really good with Sybase.
If it's only hadful of media/images you are concerend with, import it to 6.0.. If there are too many tapes/images and you can afford to freeze these tapes, you can copy part of image catalog after recovering it on standby server. Again, it's not a straight forward task. If you are not careful enough you may end up overwriting your current images. Process for recovering from image catalog without importing tapes is posted in couple of threads in this very same forum.
Good Luck!!