Go to

http://www.simviation.com/fsdesign_panels1.htm

and download cfgedit. It has been a while since I used it but I recall it to be an easy to use program where you simply drag the new gauge into position and the program does the rest.

You can do it manually too but it takes a bit of practice. Go to the panel folder of you plane and then get the panel.cfg file up on notepad so you can edit it. you will find all the existing gauges listed there something like this:

gauge12=prop2ERKap,  800,520,222,55

You can add a guage as long as it has a different "guage" number than anything else. Then add the name of the new guage, prop2ERKap in this example. The next two numbers, 800 and 520 in the example, are the x and y locations of the guage on your panel's .bmp background picture, and the last two numbers, 222 and 55 in the example, set the dimensions of the guage. (Round guages can get by with one dimension.)

Importing guages from other ms flight sims sometimes doesn't work.

Jimski