The HJG aircraft don't have VC's so adding a FSX compatible panel (& aliasing sound) is very easy
('Alias' sound means to replace the old (incompatible?) sound with a sound from an existing aircarft in your FSX. Likewise with aliasing a panel)
To alias your aircraft to use the default FSX B737-800 sounds, do this:
in the 'sound' folder open 'sound.cfg' in Notepad
Select all - then paste in
[fltsim]
alias=B737_800\soundTo add a panel - find a FSX 2d panel (e.g a B707 FSX panel can be found
here)
Unzip the file -- you will find a 'panel' folder with the various files contained - simply replace the old FS2004 panel with the new FSX compatible one.
(You could also copy one from another FSX aircraft - just copy the panel folder into your required aircraft folder)
That is all that is required and your aircraft should then work in FSX