Hi Luis,
I've had to do this for French. It involves a series of 3 functions I created in the report. Each function translates the different parts of the number to French: Digits, Tens and Hundreds.
I have a sample report I attached. It uses the Xtreme database and is saved with data so you should be able to see the report without connecting to the data.
It took a while but it works nicely. After you unzip it, rename the extension from .txt to .rpt.
Good luck,
Brian