From Wiki
Please ensure that you have checked the content on the co-branded landing page before uploading. Any offers need to be active, codes in date and if the affiliate has specific guidelines these need to be adhered to.
Step 1: Go to "Account Manager" and click on "Current Affiliates"
Step 2: Search for the affiliate the co-branded landing page is for and then click on their ID
Step 3: Enter the co-branded landing page URL in the "Clickthrough page" box
Step 4: Visit the affiliates site and click through to the merchants site to ensure that it works