Well, it appears that part of my problem is the signal being received and the other part is the SDK not necessarily sending the signal out. I can say that when the motion sensors (MS16A) were being tested, all locations worked fine as far as sending and receiving the signal. Once I mounted the sensors, I was getting HORRIBLE range issues. It appears that this is due to metal next to the sensors (metal gutters for 2 and a metal bracket for the 3rd). I have removed the 2 with the gutter issue since they won't work at all (even with full length passive antennas). The 3rd sensor needs to be relocated, but it's mostly working (~85% of the time) by adding a 1/4 passive antenna.
Also, I can verify that metal is an issue with these even if the sensor and CM15A antenna are not split by a large metal object. I tested the motion sensor in my hand and it worked to the range I need. I then placed it on my pinball machine (metal rails and panels) and got zero reception.
I'll have to get these things working correctly before I worry about the SDK. Hopefully, installation locations will sort out all of the issues.
Oh, probably the wrong place for this, but does anyone have a solution for sealing the sensors? One of mine didn't include both of the silicon gaskets so I'm worried that water will get inside and corrode the contacts. I contacted X10 and they said they would RMA the sensor, but then I'd be paying shipping to send back a sensor (~$5 + time + gas) for a gasket that's worth <$0.01. Doesn't make sense... I was thinking just putting a spot of silicon sealant on the screw before installing...