I found Roswell W. Lee in The Handbook of Texas Online at http://www.tsha.utexas.edu/handbook/online/articles/view/OO/hvo27.html as the first postmaster of Old Warren, TX in the 1830s.

I also found this listing on Rootsweb for Pioneer Rest Cemetery in Tarrant County:

Lee, Roswell W., lot 43 block 3 (1810-1873)

At http://www.rootsweb.com/~txtarran/cemetery/cv-pioneer.htm#L

This doesn't tell us about the origin of the battery but may help others in finding some information on its first commander.