I work at WiderNet, which uses HTTrack to mirror sites on a large scale.

We understand the reasons you have for programming HTTrack to change tildes
(~) to underscores (_) in folders from websites. Using tildes in folder names
is not a problem for what we're doing at WiderNet and we'd actually prefer all
URLs to remain how they look online. 

Because we are dealing with so many websites, is there a way that we can
customize our version of HTTrack so that it does not change tildes by default?
Can you point us to the part of the code that works with this? 

Thank you,
Sherry