Telerik Test Studio and the Visual Studio Plugin are both missing the functionality to add logic, dialogs, and tests as steps. The buttons to do so are not present.
Telerik: in our latest release 2015 R1 we have enchanced offline step building capabilities and we have moved all of them into the new Step Builder tab - see related article for details http://docs.telerik.com/teststudio/features/custom-steps/overview