Hey, it doesn’t really help, as the second link is actually meant for theme developers.
I have a fix, the one provided in the second comment. Having that placed wherever $custom_title is used, in td_block.php does the trick for the custom block titles.
It’s just I need to put these in each time the theme is updated, which is not very cool.

Hey Marius, any news about this? Seems it’s still not ok – can’t translate side widget custom titles (ex. the social icons widget).

Until we get a reply, I have added the following code to the get_block_title and get_block_title_raw methods, in td_block.php:

if (!empty($custom_title)) {
     $custom_title = translate($custom_title, 'newspaper');
 }

Would this be something you could include in a later version?
Thanks,