Hi,
May I suggest you to have a look at SPAD.neXt software? This impressive multipurpose tool can do a lot of things but among others it can replace FIP original drivers to handle gauges from multiple creators.
Here are some iniBuilds A310 and PMDG 737 samples. I created some of them and can confirm that side buttons are fully functional with SPAD. So are their LEDs that can be used as annunciators too.
