Getting credit for affiliate links

[cuongd]

I am a merchant selling goods. We have an affiliate program on our website.

Right now we have an affiliate program which is being powered by this company called affiliate shop. The thing I don't like about affiliateshop is when we have an affiliate sign up for our program it doesn't provide a direct link to our website. Instead it goes to something like http://coldfusion.affiliateshop.com/wid=0001234
What I would like to do is have what is called a direct link so that we get PR credit for the link with the search engines. (eg. http://www.ourwebsite.com/wid=0001234) What can I do to have such a thing into play on our website.

I was thinking about going with this company called Direct Tracks, they require you to have javascript on the landing page so that it would redirect the vistor to their server and get credit for the link. There is another company called Nettraction that provides the direct link through a redirected subdomain (eg http://affiliates.yourwebsite.com/affiliate1.html)

Which method is better? What other alternatives do you people recommend?