HTTP Connection Manager Connectionstring, Web Tasks, And Runtime Configuration

At one point in my package I call a simple web service that kicks off a process on a remote server using a Web Service Task . I need to be able to point the task at a test instance while I'm testing and a different one when it goes to production. The simple answer (you'd hope anyway) is to just store the ConnectionString for the HTTP Connection Manger in Package Configurations for TEST and PROD. I did this and when the package runs, the connection manager's connectionstring does get changed, but the web service task doesn't use this value. It uses the value defined in the WSDL file which in my case contains the URL for the TEST instance.

Am I missing something obvious? Do I really have to get the WSDLs from PROD and TEST and deploy both of them to the appropriate environment? What does the ConnectionString in the HTTP Connection Manager actually do then?

Thanks for any insight you might have.

Kevin S