amirb,
As a disclaimer - the 1422 LVDS was not designed to take in multiple cameras on a single cable so you will need to do a lot testing for this. As far as giving each camera an identifier, one way to do this is to use the DIO lines to identify which camera is connected. You cannot change how the driver identifies the cameras connected to the card, but you could send a signal on the DIO lines and poll this for identification.
What kind of multiplexing are you using?
--Michelle
National Instruments