Using a local npm module and mup

With v1.6 of meteor, and perhaps later 1.5 versions Im having trouble deploying an app that includes a local npm project whose dependency is referenced in the applcation package.json as "mymodule":"file:../mymodule". This way of writing the dependency used to copy over the relevant npm tree of dependencies to my meteor project but in 1.6 it creates a symlink which works fine in development mode but means that mup doesnt include all of the relevant modules when it creates its build. The meteor documentation suggests using the command meteor npm link mymodule but this just seems to make the symlink. Is there a better way to reference my dependency? Or should I raise an issue with mup?