Hi,
As Damien suggested, information about this conversion process is indeed available over on the ResExcellence web site, via a search for 'appe' or 'background'. I saw that your own
Invisible Applescripts post in the ResExcellence
User's Forum has gone unanswered so far, but there are some older relevant threads in that forum.
Such threads include:-
Applescipt into Extension?, and 'Converting apps to background only' [which doesn't seem to be online anymore, but there's a copy of it in my iDisk's Public folder ('pcrawford : Public :') at the location ': Develop ƒ : Documentation ƒ : ResExcellence™ Posts : Processes : Converting apps to BOA']. If you do decide to go ahead with the 'APPL' to 'appe' conversion, be sure to heed the various warnings and caveats mentioned in those threads.
Regards,
--Paul