Putting new gauges into the VC is not possible unless you have the source files for the model. Gauges can only be placed where there are 'holes' in the panel for them, and the 'holes' are made when the model is made.
-SNIP-
Anybody can correct me if I'm wrong. But I'm pretty sure that's the way it works.
This is only partially true. It really depends on how the VC is modeled
to begin with, as the post following yours states.
In the case where the VC isn't an open pallete, there is often a gauge
that you can 'do without'...a clock or somesuch.
Just use the same coordinates for that gauge and see how it 'fits', then
adjust them and the dimensions until you achieve a workable solution.
I've done this on several FSX models.
A tool such as FSPanelStudio is very helpful when it comes to
gauge addition/replacement operations.
Paul