Hi Jacobo,
I'm experiencing problems with xelatex and unicode subscript numbers. They work well in osx applications like Texshop and openoffice but they are not displayed in the final pdf generated by xelatex.
Have you made sure to load the appropriate fonts? (is there a \package{fontspec} and \setmainfont{My Unicode Supporting Font} line in your preamble, for example?). TexShop and OpenOffice pick their own "whichever works best" fonts, XeLaTeX will only use the fonts you tell it to.
- Mike "Pomax" Kamermans nihongoresources.com -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex
