To set up the Payment Express payment gateway:
1. In the AspDotNetStorefront admin console, go to the Site Configuration Wizard page.
2. In the Payment Gateway section, click the 'configure' link next to the Payment Express entry.
3. Put in the values you obtained from Payment Express for the 'Username' and 'Password'.
4. Click 'Save and Close'.
5. Select the radio button next to Payment Express, then click the “Submit” button at the bottom of the page and your gateway setup is complete.
NOTE: On 8/30/2011, Payment Express is changing the URL for their gateway. After that date, the PaymentExpress.URL AppConfig will need to be changed to: https://sec.paymentexpress.com/pxpost.aspx