Ancestry.com has the microfilm roll titled:
Selected Records of the War Department Relating to Confederate Prisoners of War, 1861-1865

It contains an alpha list of prisoners taken from Willis Battalion at Citronelle, AL on May 4, 1865, including their place of residence. Image # 45282 thru 45284 definitely say "willis' battalion"

Sorry, I don't know enough about the rest of the legion to look for it. I tripped over this while searching a person I didn't even know had served in the civil war. Wow.

http://search.ancestry.com/Browse/view.aspx?dbid=1124&path=Confederate.Selected+Records+of+the+War+Department+Relating+to+Confederate+Prisoners+of+War%2c

Hope this helps someone!