We are currently working on the Designer 2.1 release which will be big because of a huge number of bug fixes and some new features (you can get the latest until the official release from people.redhat.com/tsurdilo/designer/master).
I'm expecting to find time for JBPM-3168 after 2.1 is out. If you need this out sooner than later, community help would be more than welcome as always.