Enabling external links on a Ubercart site

From what I can see to allow external links on a drupal ubercart site you need to upload a external link module. I have uploaded a module and when I go into my module list it is nowhere to be found. Can some one tell me if I am going about this the wrong way. Is there a way to do this without a module? Which is the best module to be used for this? I have found a couple.