1. I created custom module shopuserregister drawing on kernel/shop/userregister.php (there you can create new fields, like phone)
2. I made URL wildcard or alias (some time has passed, can not remember) shop/userregister -> shopuserregister/shopuserregister
3. I made shopaccounthandler (shopuserregister/shopaccounthandlers/customshopaccounthandler.php). In this file I get previously created custom user info.