If the LHA files are on the same machine as the emulated Amiga then it is an easy task to just "find" them and unLHA them. You could use a shell and command line but easiest would be to use DOpus (4.x). If the LHA files are not on the same machine then I would suggest copying the file onto a PC 720K formatted disc (if it isn't larger than about 713K) and transfer to the emulation machine, then do as above.
I don't see the need to use ADF file.
Pete :-)
