SSRS Connection question

We have set up DNS names for our sql servers so the name Report server points to a particular instance of sql server on one of our servers. So if we want to repoint all our existing connections to a different server we just change the DNS setting.

This works fine in connection strings such as in c# scripts. However when setting up data sources for SSRS reports it doesnt accept the DNS name as a datasource but requires the actual SQL Server name.

Is there a way around this or is it just an SSRS limitation?