I think I know what you are asking. When asked to hold 10 south of a fix, there is no fix. First thing is you must define a user defined waypoint (they will clear every powerdown). This eludes many on the UNS-1
Easiest wAy to do this is press DTO, and instead of a fix, type your own name for what you are about to define. So if its hold 10 south of Sea vor, I call my fix 10SEA (must be 5 letters).
When you type this fix and press enter( you can now define where it is located. In this case I would use the REF WAYPOINT fields. You'd type SEA for the waypoint, then 180, 10 nm.
Then, you can proceed direct to that waypoint. The rest above would be on the maneuver page.
Did I answer that?