Credit Card Numbers

I didn't know where else to post this, so if this is the wrong area, I apologize.
I have a client who had us build him an e-commerce site tied into paypal.  Well, he is tired of paypal and wants everything centralized.  He has an in store payment processing system that he uses and now would like to use that for his e-commerce store as well.  So he wants to manually enter the credit card numbers into his payment system in the store.  Only problem is I would rather not store credit card numbers on our server.  Does anyone have a solution so that I can securely get him the credit card numbers without storing them somewhere?  He said as long as he can run it once for the sale he is happy.  Any ideas?
Thanks,
Chris
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