hm...
Yeah i've had that emulator that uses .ps2 files as well.
Changing the extension would be pointless as it dosn't change the way it's encoded. It would merely leave itself unknown as to the file it is to be opened with, and even once specified it still wouldn't be translated correctly because it's still whatever it was originally.
of course the guy who stated it probably knew this and was joking lol.... but still...
Anyway. I don't believe any such encoded file exists. Thus the one you have is a fake. I once downloaded a program which pretended to emulate and get an error in the emulation, when in fact all it was doing was generating a random number, and it was created with VB. There are many such fake programs out there which are made to look real, such as the one you probably have.
Sorry man, perhaps you should help contribute to this one which at least has an official page eh? Then maybe you can finally have a real one that works (eventually).