So given that signature (which is UEI's way of identifying the firmware in the remote), we can say that while the external appearance may be similar to a 7556, internally it is completely different. The 7556 is a JP1.2 remote with a Motorola micro, while 3179 is a JP1.3 remote with a Samsung micro.

If you're fiddling with VPT or channel lock, the instructions supplied with the remote may be incorrect. See the 9XX command instructions for a correct explanation. Note that this remote can do device specific macros, which only run in a given device mode.  Program it like a 995 command except use 978.

Anyway, it is true that you can't reassign the cable button to a different device type through the 992 command. It can be done with a JP1.3 cable (Tommy Tyler makes the best cable-by far- and sells it for $30). You can also use the two device 994 keymove command to setup the cable button with any signal that can be sent by another device button. You just have to program each button.

If you have a particular CD component in mind, post the model number, and we can probably suggest a setup code that will operate it.