I understand from all the literature that the 921 is UHF only. However, I can control it with IR inputs from my Harmony 659 universal remote!! Yet, I cannot use the 921 to train the Harmony, nor do the 921 remote signals show as IR signals with my IR extender and I was unable to find any spot on the 921 where the extenders would work. Can anyone enlighten me as to how this works?