George --

It might help to find the state militia laws under which these men were recruited. Confederate military laws held priority over those of the state, but it was up to the authorities to enforce Confederate and state laws. Any conflicts or questions (and there were plenty) went through the court system.

Obviously state troops were expected to serve within the borders of their home states, and it took special dispensations for state troops (such as the Missouri State Guard) to operate elsewhere. I'm sure Texas State troops and their oficers felt no differently about the matter.