Can't Create Global Products or Categories

Hello,
I'm trying to build a Multi-Vendor site based on this suggestions:
https://premium.wpmudev.org/forums/topic/marketpress-multi-vendor-support#post-123999

But I'm unable to create Global Products or Categories,
Right now, I have 2 sites on my network, with his own stores and I have enabled the Global shopping cart. Anyway, when I go to http://mysite.com/marketplace/ (where the site should show the global products) It doesn't show any product and I can't figure out how to do this.

Any help is welcome,
Thanks in advance!