I just saw your message and wanted to add a few points.
I have been researching Col. James B. Likens' 35th Texas Cavalry for many years and am working on a regimental history.
Your ancestor was in the same company as mine. A person has letters from an ancestor who was also in the same compnay. These letters will be published in book form by the University of Tennessee Press in 2006. I am going to check to see if your ancestor is mentioned in any of the letters.
There are no muster rolls at the Texas Archives and no muster rolls at the National Archives for Company "E", hence the pension as proof of service. Company "E" was originally Company "A" of J.R. Burns' Cavalry Battalion but, sadly, no muster rolls exist for any companies of Burns' Cavalry.
Col. Likens is buried in Houston, Texas at Greenwood Cemetery with a VA Headstone that denotes his service in the Mexican War and WBTS. The Likens' surname lead to various phonetic spellings like. Lykins, Lackins, Likans, etc. so I strongly suspect your ancestor served in the 35th Texas Cavalry.
Men from the same area also served in the 7th Texas, so perhaps your ancestors enlisted in the 7th then transfered to Likens' 35th? You might want to check the Compiled Service Records from the 7th just to be sure, because Burns' Battalion was not created until 1863 and the pension says 1861 as the year of first service.
Please contact me.