I know that the iPaq's have what they call "consumer" grade IR. Apperantly there are a few different grades of IR. Industrial, Consumer, and well...ghetto. :P I guess thats why these extenders work better with the iPaq.
Now, I have Nevo universal remote control software, and I love it. It's fantastic. I have each room in my house on here, and I can also use it to turn on light with IR plug adapters. With the downloads, this is one of my favorite programs.
So if you get an IR extender, I suggest you try Nevo out.
www.mynevo.com.