Peter,
We were not able to complete this feature (support for code synchronization in a multi project scenario) prior to the release of 9.0.
Depending on your needs, you may be able to extend the scaffolded service to allow you to add your own code to the implementation without requiring that the methods be synchronized back to the DSL layer.
I am sorry we were not able to complete the work on this in time to make the release.
Let me know if you would like to talk through other options.
You can reach me at [email protected].
Thanks
Jack