Hi there,
all you have to do is to send the chip address (10001000) and the data to control the chip (01011000 which will switch the chip to stereo 1 with 0dB of gain), I don't think I have to write anything else to it.
You can get the datasheet from :-http://www.angliac.com/st/data_from_st/1491.pdf
see if I have missed anything out.
Thanks.