1: Is it possibile delete the 2 buttons with javascript on cart and show always the choises of Payment and Shipment (see tha attachment)
2: Is it possible choose a kind of Payment and a kind of Shipment without click on save button? the better way is save the choises when an user click on "ORDER CONFIRM" or use ajax

So basically you want to go back to the std VM checkout?

If you want that the choices are always on that page then we can't help you with this except to suggest that the templates for them are
select_payment.php
select_shipment.php
in the templates/your_template/html/com_virtuemart/cart/ folder

You will need to show them in the default.php some how...

2. question

No, this is native VM - some onepage checkouts have this - sounds like this is what you want

then you would need to disable our cart entirely

rename templates/your_template/html/com_virtuemart/cart/ folder to something else

Cheers