Typically, an SCM component corresponds to a development project (such as a Java project). To change the structure of the component in any way, you should load the component, make the change to the corresponding project, than deliver the change.

The names pkg1, etc. suggest that you actually want to add a Java package (which is a good example anyway).
- In Eclipse Client you load the component - the corresponding Java project is created in your local workspace (not to be confused with the repository workspace)
- In the Package Explorer view you right click on the project and select New->Java Package
- In Pending changes you will see the added folder corresponding to the just-created package and you will have an option to check it in and deliver.