Someone knows how to translate the dialogs to spanish?

For a translation you have to edit the .dlg files. Just make sure you keep the scripting part intact.
Dlg files are plain text, so any texteditor can do it, although I would reommend something a bit more sophisticated than notepad.

If you use Co8, most dialogs should be unpacked.
If you don't use temple+ you can keep your edited files in the apropriate /data subfolders, else you have to put them in /override, keeping the subdirectories.