Well, if you are into mapping keys then the best advice would be to use the ScriptEditor. It makes life far more easier to program the Warthog to your liking.
And you only have to press the big ?-button to get the PDF manual that has a very detailed explanation of how it works.
Best to first have a look at one of the example files like DCS FC2 Mig29.tmc so you get an idea.
The answer in the editor for your question is that you use the MapKey command with the IO added. Then "I" stands for the shift key pressed together with another key.
The shift key has been defined to S4 in this tmc file.
For example MapKeyIO(&Joystick, H1D,View_Down_slow,
Trim_Up); gives you two different commands.
The first one works when you press the shift button together with HAT 1 down, the second works when you press HAT down without the shift key.
All the different commands you see are defined in the file fc2_MIG_29_Macros.ttm.
Hope this helps.
Sorry Joe, my answer overlapped yours. Hope it's not confusing now...
Last edited by hsth; 11/19/10 11:25 PM.