ok, the stream really has 4 channels (2 instrumental and 2 vocal) however, has noise especially in the voice. not much about adpcm (sorry), but it fails to rebuild the header: http://www62.zippyshare.com/v/17744223/file.html
to unpack the file uses a BMS script (works most of the files): quickbms script: http://pastebin.com/m7ZbTFer another bms script: http://pastebin.com/QXsWPDCy *.rev file struct (incomplete): http://www28.zippyshare.com/v/62687997/file.html