Jeff,
Have you asked the wheel manufacturer for advice on this mater?
If this were my problem, after I have found the location of the air leak as Keoke has suggested, I would examine the wheel to determine the cause (failure of the sealant, loose/broken spoke, bead seal, etc.) and address a resolution to that problem first. I then would evaluate the extent of the sealant repair needed and if small, clean the area and try an RTV fill. Once the RTV cures, I would provide additional support to the RTV fill by applying a tire patch over the area making sure that the patch reaches well past the RTV and secures to the original sealant area. After remounting the tire, I would inflate with much more then the standard driving air pressure and test for leaks again. After installing it on my Healey, I would go for a little test drive.
However, if I were not confident in my repair experiment or my ability to affect a secure repair, I would call the manufacturer and follow their suggestion. Since this can not be a condition that is unique, I would expect them to have a standard repair procedure that would probably involve sending back the wheel to them or their local agent for a certified repair.
Hypothetically, this is what I would do if I were faced with a similar problem. However, this is also the type of problem that has kept me using tubes.
Good luck,
Ray (64BJ8P1)