CGI/PERL or PHP redirect to and from eBay

Hi there, We have a fully functioning number plate design system on our website [login to view URL], operated by an external provider via an iframe. Many of our competitors operate in ebay, where the system functions as follows: * people go onto the ebay listing and enter the plate details * On pressing finish they redirect to an external page to preview and confirm their plate * Once they have confirmed the purchase, they are taken back to the ebay listing they were on previously and "buy it now" is selected automatically. I have no knowledge of CGI / perl which is what our competitors use to achieve this. I believe it could also be achieved in PHP, but I am not skilled enough. We need the system to pass the plate details too and from the external site and back to ebay, as the plate designer is too comprehensive to embed in ebay listings, plus ebay do not allow iframes. I have an examples of the competitors for you to see. Can anyone help??