Need to migrate old site (Opencart Copona) to new site (Prestashop). I repeat - opencart is NOT standart. It is COPONA (Opencart based).

The work is possible on our servers only.
The standart opencart-prestashop migration tool from prestashop store will NOT work. Need a database based solution.

Need to get done asap. As i already have dev that can not do this for 2month (promised two weeks), i have frozen deposit here. So i kind a dont believe that it is possible to get it done here. But if you can then you got fee + bonuss if get it done fast