When using the Analysis Services Execute DDL Task within an SSIS package, any expressions defined for the MSOLAP100 connection manager pointed by the ConnectionName property of the instance of ASExecuteDDLTask are not evaluated after the evaluation that occurs on package load (when ComputeAllExpressions is called from CPackage::LoadFromXML), because AcquireConnection is not being called for that connection manager, point at which it would detect the existence of expressions and would recompute them. The implementation of ASExecuteDDLTask doesn’t instantiate a connection from its connection manager (by calling AcquireConnection), instead it passes the ConnectionString property of the connection manager to another class which will use it to instantiate a connection to the instance of Analysis Services specified in the connection string. If the connection string is based on an expression, don’t expect it to work then.

This is a defect which I just confirmed and for which I filed a defect so that it gets fixed in a future release.