You shouldn't need any extra cabling to be able to control or interface
with your SCXI-1160 relay module. The 1160 can be controlled from
the PCI-6221 M-Series card (via the 1349 adapter), and the 1324
terminal block provides the interface for the relays. Check out <a href="http://zone.ni.com/devzone/conceptd.nsf/webmain/42d9648ab8c4102b862570890073ec2d" target="_blank">this tutorial</a> for more information on connecting signals to the 1160.
Try installing the 1160, adding it to your SCXI chassis in MAX, and try
switching with the Switch Soft Front Panel. Let me know how this
goes.
Have a great day!
Travis W