Every user can use programs like fdisk or cfdisk to create a Dos fat16 or fat32 partition and format it with the mkdosfs command. However in your case you need to boot up the Dos in that partition and therefore it needs to have the Dos boot loader transferred.
I use Dos but not a lot and the way I know to transfer Dos boot code into a partition (not MBR) is by either "format c:/s" or "sys c:", both requiring the user to boot up a Dos system so that Dos is in operational mode to execute format or sys.
You could try to put Freedos in an external hdd as I have installed Freedos in this way before
Others may have a better idea.