I was getting very frustrated trying to find out why the hell my IR-543 wouldn't work with my RF-6 or my T2 in IR mode. Well, after many a trial and error, I tried messing with the level control on the back of the RF-6, and found that if I turned it all the way down, the IR-543 started to blink to signal it was receiving a signal. I then left the level all the way down, and put the emitter about an inch to the right of the IR receiver on the IR-543, and it's worked flawlessly ever since. I guess the IR receiver on the IR-543 is just a bit too sensative for most emitters.
I hope this helps out those with IR-543/RF-6 woes!