Shopp Plugin and Multi-DB

I want to offer a shopping cart for my WPMU users, and after much research, including this post on the WPMUDev forums, I decided to buy/install the Shopp plugin.

The install went OK, except I found out it doesn’t work with Multi-DB. The ‘Shopp’ menu, which is supposed to show up on the left (after comments) on plugin activation doesn’t show. (Screenshot)

I verified this by disabling Multi-DB, and re-activating the plugin. It worked.

So, I re-activated Multi-DB, and did some more research. The Shopp plugin runs all its pages through /wp-admin/admin.php, like this:

/wp-admin/admin.php?page=shopp-orders

/wp-admin/admin.php?page=shopp-customers

/wp-admin/admin.php?page=shopp-settings

I thought perhaps the issue was only with the menu, so I tried to manually type in the URL (www.my-wpmu-site.com/wp-admin/admin.php?page=shopp-settings). The page didn’t show up; instead it redirected me to my default blog dashboard.

Can anyone help troubleshoot this issue? With Shopp emerging as the clear winner for simple WP shopping cart integration, it seems this would be a great value add for WPMUDev.

Note: I also opened a thread on the Shopp forums here.