In Visual Studio 2005, any Task that is added from an Add-in or a Macro using the TaskList automation object appears under the ‘Add-ins and Macros’ provider drop down in the TaskList. Currently there is no direct way, using the Automation Object Model, of selecting that provider to make the tasks added visible. To do this the best way is to call Commands.Raise using the following parameters: 

DTE.Commands.Raise("{1496A755-94DE-11D0-8C3F-00C04FC2AAE2}", 2200, "Add-ins and Macros", Customout)

This method can also be used to bring to front other providers such as the Comments or Shortcuts by just replacing the string ‘Add-ins and Macros’ with the provider names.