I’m using the Commodore A2386SX BridgeBoard in my Amiga 2000.
With JanusTools you are able to create a partition on your media which can be partitioned with FDISK and later formatted in DOS. I use my CF Card SD Adapter with a 16 GB SD Card as example here.
Keep in mind that MS-DOS 6.22 supports a partition with a maximum size of 2 GB.
Be sure you have BridgeBoard Janus 2.1 and JanusTools installed.
You can now use AREAD or any other tool to copy files to this DOS partition.