Hi Ted,
The CODM of HW4 is able to intelligently create an ODF using either wav or hbw files, so swapping an encrypted rank with an unencrypted rank is fine via the CODM. Just remember to make sure that when you load the Custom Organ using the Design Tools that you re-create the cache.
If you are talking about swapping encrypted for unencrypted ranks without recreating the ODF, then I'm afraid I have not tried that and we'll have to wait for Martin to inform us.
Kind regards,
GrahamG