Here's a well-kept secret: The Polish Joomla! Centre Translation Team have made a language plugin for Joomla 1.5.4 called pl-PL.joomla1504-admin-site.zip, available
here
and although it is not advertised as such, it contains a complete translation for CB1.2RC2. It installs out of the box as a Joomla language pack, meaning no CB plugin work is required. Amazing! That's another one off the list.
Question... is there any trick to get CB translated with this method? I have the whole site (1.5.6) translating ok, and the admin language translation set up, but CB (RC2) is still not in Polish. Any ideas?
I'll try your suggestion and dig around some more. What I was trying to find out is that I did what the post suggested and it did not work as described, so I figured maybe the secret is better kept than I anticipated