David Musgrave announced that Menus for Visual Studio Tools Build 9 for Microsoft Dynamics GP 2013 Released
Menus for Visual Studio Tools Build 9 for Microsoft Dynamics GP 2013 Released – Developing for Dynamics GP – Site Home – MSDN Blogs
Development & IntegrationMicrosoft & the GP EcosystemGP 2013
Archived post from 2012. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.