I am working on (almost complete) a revision of research I have done on the Confederate prisoners of war held at Camp Randall, Madison Wisconsin. It is called "The Boys At Forest Hill" The Confederate prisoners who died while at Camp Randall where buried at Forest Hill Cemetery. A southern born woman name Alice Waterman took care of the graves untill her death in 1897. She always called them "her boys".
I do have some black and white images of some of the flags captured at Island Number Ten. One has a inscription on it "Mississippi Devils" another has a inscription "Perote Guards", this one is from Alabama, it has the State code of arms. Maybe that is what you are looking for. This flag was returned to the State of Alabama July 27,1905.
I hope this helped.If you need any more information please call to make sure I get the message.

James Heberling
4801 Roigan Terrace
Monona, WI 53716
608-204-9232