I have a MA-200. I plug a mic into the audio 2 jack. In the vcr set up menu I set audio 2 to mic and I hear nothing but when I set my audio 1 input to mic and plug the mic into audio 1 and I hear it. My goal would be to record the camera mic and the external mic at the same time and spli the audio between the left and right channels.
For recording 4 audio channels w/ the MA-200 make sure your external mic is plugged into XLR inputs 3 or 4. XLR inputs 1 or 2 on the MA-200 should not be used, otherwise the on camera mic won't be recorded at the same time. IN the VCR setup menu choose: Audio Mode "12bit ST-1,2". Still in the VCR setup menu, set Audio 2 to "mic".
Behind the audio door make sure the audio 1 input is set to "mic". This will allow the on camera mic to be recorded on channels 1 and 2. Then plug your external mic into channel 3 or 4 of the MA-200.
Make sure you're using the audio moitor switch correctly by setting it to listen to all 4 channels at once. I used to forget to cycle through the modes for listening to the first two channels, then channels 3 and 4 , or all 4 at once.
BTW, all of this is discussed in your XL1S user manual starting on page 51. If you don't have one you can get a PDF version at the Canon webiste.