Virtuemart - disable all options of the checkout process, edit information gathered

I'm trying to disable all the options of the checkout process. Also I need(due to this project I'm working on) to edit the information asked at checkout, to ask some specific questions my clients has to do in order to process the order.

Does anybody knows what are the php files That are needed to edit in order to get this done? In the Virtuemart admin optio开发者_C百科n there are 2 checkout options that can't be disabled; why? Does my joomla admin user doesn't have the access to it?

It's not possible to disable payment and confirmation without hacking the core. Even if the user is not paying, like a purchase order or COD, the system still has to know how payment is going to be made. The confirmation page is the page that commits an order to the database, without it orders would never be completed.

As for the registration fields, you can manage those through the VM admin in the Admin menu click Manage User Fields.