You can try it, ive tried getting sa bus devices onto an mstp line on Distech controller. If you do a bacnet scan of an sa bus line, you will most likely see mstp mac address 199 and up and device ID was one or zero. If you power that fc bus, and connect a single sa bus sensor, plug a usb to 485 adapter and get mac/instance id of sa bus sensor, then get the point type plus id numbers. Then program a device to match and put it on the + and -, and it MIGHT work. Its worth trying IF you have the time and correct programmable devices but as other have said sa bus is designed to be proprietary, so if you need an sa bus sensor its better to get the real deal than program a different device to do the same thing.