I just found one of my two remotes for my old Echostar SRD7000, which is identical to a Houston Tracker 8. I put new batteries into the remote, and tried it out,
aiming it at my RS pyramid, because the pyramid flashes a light whenever it sees an IR remote transmitting.
Unfortunately it didn't see anything, so I'd have to say that the Echo/HT remotes from this era, (which I think is slightly prior to the Legend), did NOT transmit both. Ie they seem to be UHF only.
However, the Ledgend MAY be different. Because my SRD7000 (and the 2 broken HT8s) didn't have a separate UHF module, the UHF was built into these receivers. I have an old Monty 55, which DOES have a separate UHF module, and it DOES have both UHF and IR. So there is still a chance. If nothing else works, I might be convinced to part with my SRD7000 remote, since I can't even find the receivers in my junk pile, so I MIGHT have thrown them away for some reason.
But I still think your best bet is to try the HTS device in a RS universal remote.