I have similar experience as Pentit. I paid 35 dollars for Wilco A320. The panel was not operable and I replaced with Microsoft A321 panel. With this I was able to fly the model as usual but all the gauges at VC disappeared.
I have also download Overland payware for A340 but I did not like the panel and replaced with Tom 340 panel. To reinstate the missing gauges at the VC, I have replaced the whole of VC text in Tom panel.cfg wordpad with Overland VC text followed by copy overland gauge folder and paste into the flight simulator main gauge folder. When I flew this model, everythings were fine. This could not be done for Wilco as I could not find Wilco gauge folder.
Anyway I am happy with what I have as I am able to fly my favourite livery on these two models.