Microsoft has published a TechNet Wiki "How to create a Workspace Package on MED-V 2.0" written by Microsoft Partner and MVP Leandro E. Carvalho -- walks you through creating a new Workspace Package using Microsoft Enterprise Desktop Virtualization 2.0:
"Before users begin to use the old applications you need to create a package containing an image of Windows XP. MED-V will be responsible for installing and configuring the advanced options during the process of creating the package. All this is done via the Workspace Package MED-V, as explained below.
To create a package containing a virtual machine (VM) in MED-V Worksplace, log on as administrator and open the Workspace Packager MED-V on the path Start> All Programs> Microsoft Enterprise Desktop Virtualization> MED-V Workspace Packager. Then click Create MED-V Workspace Package."
The Wiki is embedded below, you can read it here or at source: