How to use old gauges in FS2004.

I have received a lot of questions on how to have old gauges working with my panels, because normally when FS2004 is starting, it says that could not find such gauges,etc..etc..
The problem is because most of the gauges were written for FS2002,FS2000 or FS98, and don't work properly with FS2004, but we can manage that situation by doing some simply tasks.

By Paulo Afonso Pizzato.