MarketPress Installation

Installation question.
Downloaded MarketPress.
Dropped the includes directory and sub directories into /public_html/blog/wp-content/mu-plugins/.
Original free version is in: /public_html/blog/wp-content/plugins/wordpress-ecommerce/marketpress-includes
I had been using the free version.
I don't see the new version on my WP Plugins page. What to I need to do to complete the install?
Thanks,
Tom