According to the book Polignac's Texas Brigade by Alwyn Barr, Camp Kiamichi was located near Doaksville in the Indian Territory just north of Clarksville, Texas. The 15th Texas Infantry did serve in the Indian Territory for a few months during the winter of 1862-1863. The above mentioned book is an e-book and can be found at the following link:
This book may not have the exact information you want but would probably be worth reading. It may refer you to some valuable primary source material. I would also recommend checking old Texas newspapers for a list of casualties.