I do the following ...
1) Transfer the ADF to RAM: or DH0: via null modem and Amiga Explorer (also you can use another soft).
2) Translate the .ADF image to a real floppy with transdisk (comes with UAE).
Also is possible to simply Drag and Drop an .adf file located somewhere in the PC to DF0: from the Windows Explorer (if you have Amiga Explorer, of course), it will automatically write the image back into the DF0: in the Amiga, generating the useable diskette.
This method is the simplest and fastetst I know.
Good luck !!!