Localisation not complete

Hi,
I’ve been asked today to translate the “Submit Comment” button that I had on my comment forms. I thought at first that I didn’t have the latest translation file and ended up downloading a more recent one, but to no avail. Then I searched my entire files for that string and found it in the comments.php file under my active theme.
It would be better if that string could be localisable by the mean of a .mo document in the next releases. It’s only a very small piece of code to add, isn’t it ?

Cheers.