problem with membership and buddypress installations creating a sign-up fault

HI - I have just discovered a big problem in my website configuration which I need some help with ASAP!
I have Buddypress, Membership Pro and the Directory plugins installed and I just discovered that when you follow the link to sign up on my site you are directed to the page that I created which has the subscription options (levels of paid membership) but when you select the option you want and click on the register button (I cant see where I can edit this button, it appears to be a virtual page and part of the plugin setup) it takes you to the buddypress network register page to set up an account first, before taking the user to the payments link.
-If a user completes the network set up/registration form and then follows the link at the bottom with the button marked 'register' they are only then directed to the paypal payment page. If the user changes their mind and follows the link at the bottom of the paypal page to go back to the site, their network membership is already active and they have already become a member without paying due to the credentials they had already had to fill out to sign up.
I discovered that if I delete the buddypress plugin, upon sign up the user is directed immediately to the payment gateway before completing any network registration information and so this fixes the problem, but then other issues are created where members then cannot list in the directory etc.
What I need to know is if there is a way that I can change the set up so that with Buddypress installed the new user must first be directed to the payment gateway upon signup instead of being directed to the network/buddypress signup page first.
I hope this makes sense as this is an important problem to fix asap!
Thankyou,
Venessa