Dragon,
Well yes Texas had a cavalry unit that was made up of Spaniards and Mexicans,actualy they had alot of units like that.Now Louisiana, Mississippi, Florida,Alabama and New Mexico had units made up of American born Spaniards and "Spanish Volunteers".A thing most people forget is that Spain owned most of the American South hundreds of years before the English ever got there. Another side not for ya, Spanish and Mexican troops in the Confederate Army didn't like eachother much,most forget that Spain ruled Mexico for about 450 years and treated Mexico pretty bad, mostly a racial thing beings that the Mexicans were "mixed blood"( White and Indian) .Also there was a few Confederate Generals that were Spanish, again, one mush be carefull not to get the two peoples confused,General Semmes was an American born Spaniard who served in the Army of Northern Virginia.
Oh the unit I think your talking about was Benavides Cavalry Regiment