[Membership 2 Pro] How to make payment a one-step (instead of current two-steps) in Membership2?

Hi, currently when a user clicks on the SIGNUP button (generated by the [ms-membership-buy] shortcode), instead of going straight to PayPal, he's being taken to yet another extremely confusing page, where he needs to click on "COMPLETE PAYMENT" button and THEN he's taken to the PayPal page.

Where do I tweak the code in order to take the user to PayPal immediately when he clicks the SIGNUP button?

Or, alternatively, how do I generate a correct COMPLETE PAYMENT button so that it would return the right information about the logged in user who just paid the payment?

Thank you