Lusofalantes são sempre bem-vindos! [Portuguese speakers are always welcome!]
Have you configured KDE for your specific locale? To do this you would need to use the KDE Control Centre:
K Menu > Control Centre > Regional & Accessibility > Country/Region & Language
and, for the keyboard, go to:
K Menu > Control Centre > Regional & Accessibility > Keyboard Layout
If you have already configured KDE for your locale but are still having trouble, see the Gentoo Linux Localization Guide
(Sabayon Linux is based on Gentoo) for details on how to configure SL/Gentoo for your locale.
If you install Sabayon Linux to your HDD and you have one or more NTFS HDDs connected to your PC, then also see the post Re: KDE 4.2 Dolphin automount NTFS on boot
on how to automount those drives and enable writing of file names in a given language.