ProRate or Future Billing Date

I am using PayPal and standard s2member plugin and looking to see if we can have members sign up today but not start the billing until a specific date. Or if not that, can we prorate billing for a set number of days so a users will not be billed fully until our specific date? Essentially we want everyone to start their billing cycle on the first of the month, but don’t want to force customers to come back on the first to sign up, we want to capture them the day they are on the site. Any ideas?