When you were substituting the gauges did you do it in the [VCOCKPIT01] section? I tried subing a few 747 default gauges and they appeared, it would just be a matter of finding suitable replacements from the stock aircraft in FSX to make this work, the 320 gauges you have won't work at all in fsx from what I can gather, (this may not be gospel, but my FSX says they're FS98 and no longer supported) If you just replace gauges in the [Window00] section I belive this only affects the 2-d panel, while the [VCOCKPIT01] affects which gauges you see in the VC.
Hope I'm [helping, I've just started to figure this out myself!!
