Integrated should provide a integrated-social-bundle with (as first) export connectors for the most important social networks.
The second one will be Facebook.
Create a Facebook export connector (http://www.integratedfordevelopers.com/content/documentation/article/creating-an-exporter-for-content-distribution)
You should be able to add a Facebook configuration which handles the API authorization
On export it will post: [url]
While waiting for INTEGRATED-999, please hardcode the URL as: /content/article/[slug], using the primary domain of the primary channel