I’m also stumped on this. When I attempt to create an Open Graph action-object pair, I get a “Create Story” dialog box with a section for actions and a section for objects. I can select “Article” from the object section, but the action section is blank. If I type “Publish” into the “Create a new action type” box, add it, and select it I receive an error message: “A custom Publish action is restricted. Please use the common Publish action instead.” I’d certainly select Publish from the list, but it’s just not there to select.
I’m sure I’m missing something, but I have not a clue what it could be.