GE NX-548E Compatability with ELK M1?

So, the NX-548E is now compatible with the M1, by using the ELK-WO35A wiring harness. How does it connect to the M1? If I have used up, say, 15 of my 16 on-board ELK zones, and I add the 548, will I need to add anything else (other than the wiring harness) to add some wireless zones? Are there any concerns with going over the 16 first zones? Is there some kind of a one-to-one mapping of wireless zones to elk wired zones? In other words, how does the M1 know which wireless zone is activated? Are there installation instructions for adding the 548 to the ELK somewhere?

I just got my NX548E working. The only catch is that you need to activate transmitters in sequential order; meaning that you cannot pick Zone 64 as a Fire Smoke. You'll need to go to the next available zone. Range is 50-60ft in my house. I will need to move the device either in the attic or under the crawlspace on the west side of my house.

I think I have heard of some people hacking their 548 antennas to increase the range. Anyone know how to do it?

I get at least 80' or range on mine, with the stock antennae and a bad solder fix on one of them from where I broke it off (will fix it once I locate my good iron), even though it's in the basement. I use a keyfob in my car to arm/disarm, and it works fine from the street and inside the vehicle (about a 10dB loss just being inside the structure of the vehicle), so in my case at least, it's got range to spare.