Translating theme after it's been uploaded on WordPress

Hello.
I uploaded a theme on a client’s blog whose hosting provider does not provide FTP access. After uploading and installing the theme, I translated it, generating a new .mo file. Normally I would place that file in the languages folder of the theme via FTP, but that’s not an option with that host. I tried re-uploading the theme on her blog, but WP informs me that it is already installed. Is there anything I can do to have her theme translated now? Thanks!

(I posted this question on the WordPress.com forum and they told me to post it here.)