More out of laziness/convenience/call-it-what-you-will I have created a an ILS for a couple of my favourite freeware destinations: I have them showing in FSCommander and would like to know if I can add that relevant data to aircraft FMCs.I have mailed the author Martin Gleeson but got bounced back. Thanks.

It depends on your aircraft/fmc model. Are these real world ILS's you've added? Does it pull any data from your installed scenery? Are you just talking about adding approach or departure navigation procedures? For most models you do not need an ILS in the database but just added to the airport (many with DME). You then write the approach in the specific airport file. In that case if the approach waypoints use an ILS DME facility you add that to the fix definitions and then specify in the procedure description the ILS fix and dme as a waypoint. Some models do autotune the nav radio but that is another file. If you are adding an ILS I highly recommend you check out ADE9X. It will also create an approach layer with default settings that you can edit such as the FAF. These are used by AI in IMC, the default GPS map, and the FS map details. Using AFCAD to add them will only affect your aircraft, not AI. I think it will also affect your runway choices in IMC (IFR) that FS ATC will offer you.