I have a dual LNB RCA DSS with 2 receivers. I'd like to watch DSS on a 3rd TV. MCM Electronics advertised a 2nd room kit (58-6460) for $40, so I ordered it.

Got the kit today and it's a Panasonic and the remote is not programmable for DSS. Have lots of extra one for all remotes, does anybody know if I can make this getup work with my RCA DSS?

If you are trying to hook up a third receiver to your dual LNB,you'll need a multi-switch that takes the two feeds from your dish and expands it to four. (or six or eight if you wanted). You can purchase one at radio shack for approx. $90.00.
If you are just trying to use one of your two receivers then all you need to do is get a piece of co-ax and attach it to the co-ax output on the receiver and run it to the third TV (Ch3/4). Hopefully the 2nd room kit will have an IR repeater so that you can control the receiver from your new location. Remember that without the third receiver you will have to watch the same program that is on the tied in receiver.

I just did what you want to do. I ordered a Channel Master 3x4 amplified multiswitch from www.gohts.com (they also explain how to set it up). Your two DSS feeds, plus an antenna or cable feed go in, and 4 outputs go out. Run an output to each DSS receiver (you will also need diplexers if you combine the signal with antenna or cable at the multiswitch). USE RG-6 !!

Best Buy sells second room receivers for $59.