And finally it works!
After several tries, I just want to discart de possibilty that the UTFT conversor was doing something that I can not understand actually, and I tried the regular arduino version of the .c file, not the DUE.
And it works like heaven. I dont really know why. But it works.
Maybe cause I'm using a shield? Maybe for the CTE display... I don know. But it works like that, and I'm happy. 