Abacus "EZ-Landmark" and "EZ-VFR" registration?

I recently downloaded and installed Abacus Software's old "EZ-Landmark" and "EZ-VFR" addons for FS2000/FS2002/FS2004 and discovered that they work fairly well with Combat Flight Simulator 2. Note that in order for these addons to be useful you have to import all of the FS2000 scenery into CFS2, which I already have done.

Now to the dilemma: Since Abacus Software is no longer around or in business, and the addons must be unlocked with paid registration keys to allow them to be used to their full potentials, what to do?

I did find one boxed copy of EZ-Landmark on EBay, but I have a hunch that the registration code that comes with it might not work with the latest/last versions of the addons that I have downloaded and installed.

(To the admins/mods: Sorry for the subforum crossposting, this applies to CFS2/FS2000/FS2002/FS2004)