There are many different services available from PayPal these days. The standard PayPal payment gateway you have is the most basic and requires only an email address. I am using standard PayPal but I use the API method to connect (which requires a username, password and signature), which is required (I believe) when you operate from a secure server - https://). This is not the PayPal Pro or PayPal PayFlow or any other of their services. It is just standard PayPal.
Is it safe to assume that I can use the PayPal Pro gateway you provide in this manner or am I going to need a different plugin?