Warning : this new version of lightning will only work with thunderbird 3.1.

Installation tips :

yum remove  thunderbird-lightning
yum --enablerepo=remi install thunderbird-lightning

Starting with 26 release, I have get locales back. This new build is installed in the thunderbird extensions folder, thus solves (workaround) Bug #608511.

For feedback or additional informations, visit the  forums.

My changes to the spec fedora spec file on github.