How do I manage environment specific connections for SSAS projects?

I am using SQL Server 2012 and I am responsible for implementing release automation for our SQL, SSIS, and SSAS projects.

SSIS projects have project parameters and you can link those to SSISDB environments so in each environment (Dev, QA, Staging, Production, etc...) you can have specific values for things like database servers, mail servers, etc...

In SSAS, I cannot find an eloquent solution for doing this for the defined external Data Sources. After I build the solution I need a way of updating the ConnectionString "Data Source" and "Initial Catalog" values in the .configsettings and the .asdatabase files so they point to the environment specific values.

The only way I have found to do this is to have an intermediate step between the build and the deployment that will go in and replace the values using search / replace. I don't feel like this is scalable and it seems like it is error prone.

Does anyone have suggestions on how this should be handled as a best practice?