Its something I do regularly, with knowledge of the layout of the .aircraft and .panel files, and a copy of "FS Panel Studio".
I use the default full Bendix-king Radio Stack for simplicity...(copied from the default Beech Baron 58 files)
You will also need the various modern VOR/NDB/HI/HSI, etc, etc, gauges to work with the Radio.
It would take a long walk-through to describe the method in detail, but a knowledge of the layout of the .aircraft and .panel files is a good start.
Positioning all the gauges, etc, using X.Y.xx.yy. coordinates is time consuming. That's where FS Panel Studio comes in handy...just select-drag-and-drop!
Paul...FS 2004....
...!