In the galaxy editor, go to the File menu and select Dependancies. Click on "Add Standard...", check off "Liberty (Campaign)" and "Liberty Story (Campaign)" and press Okay.
Then select "Liberty Story (Campaign)" and use the UP arrow button (just right of the Delete button) to move it to the top of the list, or you will run into some issues (there is an issue with the Galaxy editor if this is not at the top of the list).
After you do that and hit Okay again, it should be available, along with a lot of other things.
@martinolsson: Go
In the galaxy editor, go to the File menu and select Dependancies. Click on "Add Standard...", check off "Liberty (Campaign)" and "Liberty Story (Campaign)" and press Okay.
Then select "Liberty Story (Campaign)" and use the UP arrow button (just right of the Delete button) to move it to the top of the list, or you will run into some issues (there is an issue with the Galaxy editor if this is not at the top of the list).
After you do that and hit Okay again, it should be available, along with a lot of other things.
Have fun! =)