Global shortcode & excerpts?

Just installed marketpress & everything seems good, apart from... I'm running a multisite, and I've created a page on the main home site to display products from subsite members.

I've used the global shortcode [mp_list_global_products text="excerpt"] as I just want the featured thumb & excerpts created in the product listing, but all the products show the full description?

Anything obvious I'm doing wrong?

Thanks