DelphiBob,
What is happening here is that you need to first configure an SCXI device in MAX, and then you will be able to see the different modules.
I would recommend taking a look at this document: 
Getting Started with SCXISetup information for the SCXI-1120/D is found on page 3-8
Setup information for the SCXI-1121 is found on page 3-14
Basically here is a rundown of what you need to do in the software to confirm that everything is working:
- Connect everything and power everything on.
 - Go to Start > All Programs > National Instruments > Measurement and Automation
 - Expand the My System > Devices and Interfaces tree
 - Right click on Traditional DAQ Devices and click Add SCXI Chassis...
 - Follow the instructions making sure that the type of Chassis, Chassis ID, and address are filled out.
 - Once the SCXI chassis is created you should be able to read channels from the device by using test panels or programmatically
 
  While it may seem like a long list everything is pretty fluid and should go smoothly.
Note:  When you address an SCXI channel in traditional DAQ you have to use the SCXI Channel String which is in the format of "oba!scb!mdc!d".  Where a is the board's device number, b is the SCXI Chassis address, c is the module number and d is the channel(s) you are wanting to view.