Activate plugin automatically after blog setup

Hello everyone!

I'm using Shopp plugin to setup e-Commerce sites on Wordpress.
I would like to give my users the ability to setup Shopp sites themselves but there is only one issue - this plugin needs to be activated by hand after the blog is setup (to create Pages and Databases).

I don't give my users the ability to modify plugins (they don't have access to plugins) and I don't want to activate it by hand everytime a blog is setup.

What can I do to activate this automatically after a blog is setup?

This is really stopping me from developing my Multi Site platform at the moment.

Thanks in advance for any help!