We use MEWS Payments as as payment processor and we use Siteminder’s Booking Engine - Direct Book as our Booking Engine.  The issue is that Siteminder only payment form only acts as a ‘payment window’ to collect card details but doesn't actually action the payment or as you would expect connect to MEWS Payments to process the payment during the booking process.
We have spoken to Siteminder and their response is it is up to us to do manually.  Once the bookiing comes through MEWS Payments automatically processes payments which is fine, the issue is that the Siteminder Payment Window will accept any card and process and confirm bookings using the card that is entered, meaning that invalid and expired cards can be entered and  booking confirmation issuesd.  Leaving our Front of House with an admin and payment headache.  
Surely Siteminder’s payment window should just connect to MEWS Payments at the point of sale?
We have spoken to Siteminder and their response was to try to sell us into using their payment processors Siteminder Pay which we don’t want to do.
Any help from MEWS Payments team or other hoteliers using both MEWS Payments and Siteminder booking engine would be much appreciated.  Thank you very much