Work around WP Super Cache

I have a work around that is working on my site with WP super cache
Change the permalink to Custom Structure to ‘http://www.mysite.com/%post_id%’

Using Simple Cart & Buy Now version 2.0.0 and WP Super cache version 1.3.2
This seems to work well but haven’t tested it fully

http://wordpress.org/extend/plugins/simple-cart-buy-now/