When I automate to sequence all of my Sony PMW-200 audio comes up as single channel audio. I should have 4 channels. However, when I drag and drop an individual clip from the project window, all of the audio channels are there. There MUST be a work around to this problem. Ughhh!
similar question, I found a thread that may solve your problem: Sony PMW-200 file import into Premiere Pro CS6 only get 1 Ch. audio, you can go for a look. Or you can try some converters to help you. Handbrake, any video converter, ffmpeg,imixmxf, transcode them first, then reload into premiere.