I'm wondering if it's possible to offer more than one payment page. One for normal subscribers who are paying with a credit card, and a separate page for a different subset of subscribers who will be getting invoiced instead of paying with a credit card. Or maybe I'm going about it the wrong way...
built in in aMemeber in setup/configuration page click on tab 'plugins' and in Payment Plugins selections choose multiple payment plugins (HOLD Ctrl key to select multiple plugins). when your client now orders a product he has to choose witch payment option he or she want to use. next page (payment) depends on input from client. I use the Paypal plugin and a custom plugin for MultiSafepay that handles iDEAL and a lot of other payment options.