From the way I read an online manual it seemed you could record 2 XLR Channels as CH 1 and 2 separately, and have it record the on board mic to 3+4. I tried it to what I thought was right last time I shot (camera isn`t mine) and it ended up only recording on 1 and 2 the boom and lav...3 and 4 were silent. What is the proper way to make it record all 4 channels?