I use the complete M42 wiring and ECU, you can just put the M42 VR sensor in the M44 front cam cover but then you'll need to put some kind of spacer in between as the VR sensor is deeper. You also should change the cam gears as the M44 trigger is completely different (as you can see on the pics). I haven't done this and I don't know for 100% that the M42 cam gears fit, but my car runs fine with the wrong trigger anyway
I bet you could even skip the cam sensor, as the engine appears to run well with the sensor unplugged. But I only unplugged it and revved the engine a couple of time so I'm not sure how the engine runs under load.
I know my "solution" isn't the best but it works and I wouldn't have done it if I didn't have a Autronic SM4 ecu ready to be installed within a month or two