Order product without gateway I would like "buy" product without the use of a gateway. The reason for this is that the customer will have the option to apply for a loan at the bank and when the loan it approved we'll get a callback and then the order will be executed. 

Does anyone have a good idea for this solution?
Seems like what you're looking for is under Commerce Settings->Payment Methods, set the "Credit Card Payement Type" to "Authorize Only (Manual Capture)", then set the "Payment Gateway" to "Dummy".