If you're referring to the prebuilt glibc-locale-* RPMs provided in the mpss-X.Y.Z-k1om tarball, you should be able to install them into the card's filesystem using the same methods you can use to install a library's RPM--that the RPM contains locale database files instead of shared libraries doesn't change how it's installed. Once you've done that, SSHing to the card and setting the environment variables should also work as expected, as should modifying /etc/bashrc (provided you still login with SSH). If modifying the environment won't work for your situation, modifying programs to use setlocale() from locale.h should also work.
