Why doesn’t exist any promotion model for Windows deployed systems?

Using the Enterprise Extensions, you can define Packages, Deployment and Promotion definitions, enabling to promote Releases without rebuild them from, say QA to Staging or Production. But there isn’t any similar feature for Windows systems. We have already configured the project area with streams representing those environments (Integration, QA, Staging and Production). We can create a Release building the system from the QA stream, but we cannot then deliver the Release to Staging and Production. Of course, we can deliver the snapshot created during the build, but we need to rebuild the system in the new environment to deploy it.

Do anyone explain us the reason of this difference? Perhaps is there any other better approach to manage promotions in Windows?

We are using RCLM 6.0.2, with JTS running under Windows server 2012, deploying systems both in Windows and IBM i environments.