Thanks!

I went to try your suggestion, and realized my observation of the problem was incorrect. The 260 is re-transmitting the signal, but the signal from the 260 isn't triggering the cable box to do anything. The IR signal directly from the 450 does though. So, now I really don't know what to do.

I tried re-teaching the 450 the commands using some of the techniques in the how-to, to now avail. Right now I'm having trouble with the idea that the 260 is changing the signal somehow instead of just repeating it exactly.  What could cause this.

All devices are being fed signal at all times, I don't have the 260 setup to discriminate which signals go where.