So, you have the FileZilla server running on Windows, right?
And, I concur with these fine gentlemen. You are not going to get an externally defined multi format physical file. Keeping in mind, that we have no stinking clue how an alternative platform may even store it's file definitions. Or if a simple FTP from one platform to another will transfer file definitions.
Ok before some clown pipes in that "sure you can get an externally defined multi format physical file" let me say that this doesn't count:
RECORDID Alpha 2
THEDATA Alpha 264
where THEDATA may be defined differently depending on the value of RECORDID.