Adding new menu items for a multisite

I'm having some issues with the Easy Blogging plugin.

I have managed to add a new menu item, which in this case is the marketpress 'Add a product' option, url I have used is:

wp-admin/post-new.php?post_type=product

but the only thing it does is send me straight back to the main sites admin area not the individual sites admin area.

For the above menu item I have the capability set up as edit_posts and have also used the 'show this menu item' part.

What am I doing wrong?