UTF-8 encoding support in REHL 6.4

When I configure a non US language like es_CR.UTF-8 in the i18n file and in grub.conf, the Red Hat Enterprise Linux 6.4 does not recognize the spanish characters. They are recongnized only if I configure the es_CR locale. But this last option is not valid if I can configure Postgresql 9.3 to use UNICODE (UTF-8) encoding.

I need to know how to configuire UTF-8 encoding for properly display message in spanish language and have success when searchig strings in this language.