I'm not sure what you will have to do to actually get DOS installed. It can't install itself to any except the first disk. You may have to do some sort of hardware disk swapping to get it installed, unless someone else here has a better idea.
The other issue, making it a boot option, is somewhat easier. Assuming you are using Grub, there are instructions here: http://www.gnu.org/software/grub/man...2fWindows.html
. Basically, you are going to fool DOS into thinking it is on the first hard drive. Don't forget to use chain-loading as well.