I stumbled around trying to get my UX23A to work at the simple task of turning ON/OFF my TV, via X10 controls. And, I finally got it to work, so I thought I would put together a short summary of helpful tips.
1) First off, the operation manual sucks... This source is just a bit better (same basic info, but clearer, and gives help):
http://kbase.x10.com/wiki/Setting_Up_and_Learning_with_VCR_Commander2) The UX23A does NOT receive X10 powerline signals. It receives RF signals. So, that is why it does not work directly with a PR511 motion light. However, you can use an RF transmitter to send a powerline signal into the air, that the UX23A will receive. In my case, I just setup a macro in my AHP with CM15A to SEND RF. It works great. I don't know what other RF sending modules are available.
3) When I programmed the IR like it said to (program REC first, then STOP), it always errored out after STOP. For the REC I was programming it with my TV ON/OFF IR signal. For the STOP, I was trying to program it with just a dummy IR Command. What I ended up doing was just programming the REC only, and letting it time out (10 seconds). This worked. And, it was fine for me since the REC (in my case TV ON/OFF) is all I wanted.
4) Don't forget to unplug the IR emitter when programming IR. I missed this at first.
Now, I have my TV ON/OFF programmed into a multi-button wall switch, so I don't have to find to blasted remote as I'm headed up for bed.
Have fun!
Rob