Thanks for the hints. I did go back to the the control adjustment page and looked at ALL the options (wow!), but was still unable to get the MSFFB 'hat' buttons bound to the aileron/elevator trim controls. Looking further, I found that they were instead bound to the POV controls as shown in the attached screenshot.
I thought that all I had to do was clear the POV bindings and then bind them to the aileron/elevator controls, but no joy - I can clear them from the POV controls, but they still don't show up as options for the aileron/elevator controls.
I know the 'hat' switch is recognized by DCS, because I went back to the POV controls, cleared all the bindings, and then re-bound the 'hat' switch to the POV controls. Double-click in the MSFFB column to get the dialog up, then click the appropriate 'hat' switch, and voila! the binding shows up as 'JOY_BTN_POV1_x' (where 'x' is U/D/L/R, etc. I was also able to program 'BTN2' on the MSFFB to 'View Center'.
Why would DCS prevent me from using buttons for aileron/elevator trim, and then allow me to use those same buttons for POV changes?
On a slightly different subject, is there a way to print the results of key bindings, so I could have a printed list to reference while flying?
TIA,
Frank