I don't know about that. I've never seen a reference to Newman's Cavalry, and I thought it might possibly be a mistaken identification for what was really Newsom's (Alabama) Cavalry Company, instead. However, Broadfoot does list some men who belonged to Newman's Cavalry:

W. L. CAIN; 2nd Lt. William T. Chumley; and Burrell PACE, the subject of the original inquiry.

Now, why only these three men? Don't have an answer to that and would be interested in any speculation...