I'm not sure how it translates to the sim, but in the real world with most training aircraft you can roll the trim the whole way to the stop (towards up) and it will establish word not allowed close to best glide..within 1-2 kts.
The way it was explained to me during my instrument rating (in a G1000 C172) was the displayed identifier does count as properly IDing the navaid. You still could listen to the audio to supplement the display, but it's not a requirement unless the ID doesn't show up on the PFD for whatever reason.
Hope this helps,
- Paul R.
A more direct link that aburley pointed you to is here:
http://forums.vrsimulations.com/support/index.php/Navigation_Systems
If you are interested in how other military aircraft (outside of MSFS) navigate, you can check out the flight manual for the A-10 here: http://www.digitalcombatsimulator.com/en/downloads/documentation/
If you'd like to see an actual flight manual for an A-10A, you can download it here (the internal navigation computer stuff starts on page 1-91 or 115 if you go by the acrobat counter): http://www.476vfightergroup.com/downloads.php?do=file&id=42