I also had a problem with the Joomfish and the metadata patch, but I solved it. I added an extra field to the translation of both articles and menus in which you can translate the metadata that you added with the metadata patch. I am using it on my site http://www.skuzet.nl
. Just take a look at the site and see how it works. You can download the files on the site from the downloadsection (first subscribe and log in).
To use the files, put them in administrator\components\com_joomfish\contentelements and then you see the extra fields on the article (content) en menu translation screen of JoomFish.
The extra field is just a memo field, and you have to be sure that every parameter starts on a new line. You can just copy the text above the memo field and use that as a start.
Good luck with translating your metadata.
Please let me know what you think of it!