There should be a way for the cable tools to drop the info for a jumper into it's associated fixture.  For example, if I am using the "Assign Multicable Circuits" tool it is already assigning circuit name, circuit number, as well as dropping a cable into the drawing based on your settings.  There currently is no setting or way to have that cable input into a field in the fixture.  So in addition to assigning circuit name and number it would also put "5' L6-20" into a "Jumper" field or "10' 5pin