Captain Warren S. Lurty's Roanoke Horse Artillery Battery had a short span. It was organized in October, 1863. First attached to William L. Jackson's Cavalry Brigade it saw service in the same fights as the 20th.The members of the battery were recruited from various companies of cavalry. In June, 1864 it became a part of Thomson's Horse Artillery Bn. in Lomax's-Rosser's Cavalry Division. The battery was decimated by causalities and personnel captured, including Captain Lurty, on November 12, 1864 at Ninevah, near Front Royal, Virginia. The remnants were presumably included in Lee's surrender at Appomattox but may have escaped the actual surrender when Rosser's division cut its way through Union lines and headed for Lynchburg. A history of this unit is also available from H.E. Howard.
Graham's Petersburg, Jackson's Kanawha, and Lurty's Roanoke
Horse Artillery by Robert H. Moore, II
I have this volume if you need any info, feel free to ask.