I created an inventory item called PREPAID. I add that line to all POs that will be paid by credit card at the time of purchase. I go to enter the bill as usual but leave all item costs at $0. In the PREPAID item line, I add info of item charges, shipping cost, and total. That way the details are there for reference but the total is $0 and will show paid.

you will need to input the invoice to close out your PO.  At that time you can input the payment as your CC. change your bank account to the CC accounts payable account,.  Then when you pay the CC bill, you would code those same transactions against the CC accounts payabale account to zero out.