Pathauto

Hello,

I need to generate paths to nodes in this way by using Pathauto

[node:menu-link:parents:join-path]/[node:title].html

But this token [node:menu-link:parents:join-path] uses menu titles, I need to use title aliases.

Like
menu1 (Title: Cool Books, Title alias or Menu Attribute is super_cool_books)
-- sub menu2 (Title: Rare books, Title alias or Menu Attribute is AbsolutelyRareBooks)

So URL would look like domain.com/super_cool_books/AbsolutelyRareBooks

There are to issues
1. I am not sure where to set 'title alias', it can be Menu Attribute like CSS ID
2. How to change Pathauto behavior to generate urls in to way domain.com/super_cool_books/AbsolutelyRareBooks

These are just an idea, if you know a good approach please help me (ready-made module, or changes in Pathauto).

Thank you!