As everyone is now well aware, Facebook launched its sandbox last Friday for developers to start modifying their applications to fit the new Facebook profile integration points. Today, Facebook announced more details on exactly how developers will be able to publish feed stories.

With the profile redesign, all feed items will be templated. In order to register all 3 feed sizes at once (one line, small, and full) beforehand, Facebook has added a new method called feed.registerTemplateBundle. You can create as many bundles as you want, and in order to publish a feed story, you just call feed.publishUserAction with the template ID.

Facebook’s Pete Bratach explains the mandatory changes developers must make to their applications to be able to publish feed stories after the profile redesign is launched:

Once the redesigned profiles go live, we’ll begin deprecating the existing Feed publishing API methods (feed.publishActionOfUser, feed.publishStoryToUser, and feed.publishTemplatizedAction). The existing API methods will continue to work during the transition period to the new profiles, so you can publish stories using either the existing API methods or feed.publishUserAction.

During the transition period, you should only publish the story once, so you should make use of the old methods or the new methods, but never both. If you are still using the existing Feed methods once the new profiles are launched, stories posted via those methods will only appear as one line stories to News Feed and the Feed tab on the new profiles.

Bratach also said Facebook will announce a cut-off date for the current feed publishing methods soon. After the cut-off, they will no longer work and your application will not be able to publish feed stories.