PLLLLLEEEAAAASSSSSEEEE ANYONE, Help me find this BOOOK!!!!

[EyeSeeV]

I have been searching for this book for almost 5 years now and i am going
desperate. Has anyone EVER read a book that starts out with this Spaniard
boy who gets kicked out of Spain for spitting on some other Spanish
nobleman. He gets sent to live at his uncle's ranch in texas (or new
mexico), with his mother and his younger brother. At night, native
american indians raid the ranch, scalp everybody, and kidnap all the kids.
The older son gets seperated from his little brother ( i think his name was
luis or robert).. and is forced to live as a slave with this abusive chief
and his two abusive wives.. I don't remember too much else, just that the
boy ends up being reaaally good at horseback riding, he falls in love with
this indian chick, and the only way he can seperate her from her deadbeat,
abusive, FAT husband was if he paid the girl's parent's enough horses. So
he steals a whole buncha horses, and becomes a renowned ( i think
Comanche) warrior... Please please, this is all i can remember. I dont
know the title, year or author. I used to think the title was Komencia,
but now i have no idea what it could possibly be.... its NOT comanche moon
or dawn..

[B_elk123]

Is it Comanche Sundown?