May be I have another idea if thoses files are just a bit more than 720kb :
You need two floppy disk.
Pack the files with Winzip or something else to a 720kb PC floppy.
Format the other floppy disk on your ST in bigger format than 720kb. This will prevent Windows from reading your newly formated floppy exepted by using specific software (I don't know them).
eg : more than 80 tracks per side (up to 82)
more than 9 sectors per side (up to 11)
In that way you will get a floppy disk that could nearly reach 1Mb (82 tracks, 11 sectors = 902Kb = 923648 bytes) but that is not a serious thing to do because you may loose data as time will go. 80 tracks, 10 sectors will give you 800Kb (819200 bytes) for example is a good deal...
You may need a format/copy software to do so.
The system do not provide that but is able to read such floppy disk.
Then unpack your file with your Atari using STZIP or something else with source disk the pc-like floppy and target disk the enhanced format ones.
If you don't have two floppy drivers, it could be anoying to unpack from a floppy to an other one because you may have to swap those two so many times... So you could also use a ramdisk software. That is a more elegant way to do this kind of things.