sh404sef and Virtuemart 2rc

[kriks]

Could you tell me where is the file, which responsible for creating URLs?
I want to make VM-sef to convert characters into that i need, for example: "ý" = "yi" (not "y"!)...

P.S. I try to migrate from "J1+VM1+artiojoomsef" to "J2.5+VM2.0.4+sh404sef3.4.6", so i need to leave URLs in previous form!
Another problem is that i want to leave previous way "site.com/menu/categories/product".. But sh404sef make like this "site.com/categories/product"

sorry for my Eng