"open new window" when visitor clicks on my Paypal button

Hi,
Im up and running with the S2 Member plugin - but Im facing a problem with the Paypal buy button generated by S2 Member,
What I need;
when the visitor clicks my Paypal 'buy now' button, it opens in a new window - rather than redirecting to Paypal as its currently doing,
I have tried changing the short code but without success.
Id really appreciate your help guys!
thanks
Dan
Im up and running with the S2 Member plugin - but Im facing a problem with the Paypal buy button generated by S2 Member,
What I need;
when the visitor clicks my Paypal 'buy now' button, it opens in a new window - rather than redirecting to Paypal as its currently doing,
I have tried changing the short code but without success.
Id really appreciate your help guys!
thanks
Dan