Please help me about shareasale affiliate tracking solution.

I'm currently do 301 redirect from inner page to merchant page via .htaccess like this

redirect 301 /xx.html http://www.shareasale.com/r.cfm?B=11111&U=11111&M=11111

Code (markup):

However, I need to track keyword with url like this

http://www.shareasale.com/r.cfm?B=11111&U=11111&M=11111&afftrack=<?php echo $tid; ?>

but I cannot place this link in .htaccess due to that page is not php. The only way now I have to replace old link with this ugly affiliate direct link to keep tracking and I do not want to do. Anyway to keep this link tracking work (&afftrack=<?php echo $tid; ?>) and I still can hide affiliate link?

 

Maybe you should be asking this on a php forum, you will get much more responses there.