I have just installed a Spacer 5WC contoller and 3 switches in a single gang box and all works with the lutron remote when pointed at the switches and also if I point to the IR system in my rack which has one extended IR emitter mounted into the 5WC and another into the other end of the gang box furthest away from the 5WC.
However, when I teach those codes to my MX 900 the switch furthest from the 5WC does not respond when I point to the rack system but all switches work when I point the mx at the switches.
Any help on this is much appreciated. I also tried codes from the mx library and about every way I read to teach the codes differently from the Lutron remote to the mx. Doesn't mean I didn't miss one though.
I had this same trouble with the original remote at first when I had both IR emitters in the 5WC so I moved one to the other end of the gang box. I don't know if the result was conicidental or cause and effect but it did the trick.