Addict,
the comms cables will not need to be forced. As JK implies, you probably have the wroong end. Look at the M cable at each end and you'll see the pins are set out differently. A S-lead is the same both ends.
Your 5200's will upsample anyway I thought so you may not detect a difference even if you find an on/off switch in the G08 setting. The G08 will display 44 as that is waht it is reading. Toggle the display for the 5200's and you may see that they are receiving 88 which would indicate that the G08 is upsampling.