Provide specific checkout success instructions for one product

I am a reseller of a digital product. I cannot distribute the download myself, but have to redirect the user (once the checkout process is complete) to a URL so that they can register with the vendor and obtain the download. Please note that I cannot e-mail them the link because it is not to be distributed, so will be directing them server-side to the correct location for this.

Is there a way that I can override the checkout success page and show the link or a button if this particular product has been purchased? This seems like the easiest method for accomplishing it, if I can determine that product was purchased. Thanks.

I may have already found the answer with the "Similar Posts" listed...

http://www.zen-cart.com/forum/showthread.php?t=16720

I will try it out and see if I can make it work. If anyone has other ideas then let me know.

I guess off the top - that as a download you provide a loadable page/link that contains the required link and text about what was purchased.

This way you can control the # of times accessed - and control this as not an open link page that could be compromised