Customizing Content Pages
To customize content pages, you can use extension points for the CentraSite Business UI and implement Java classes and methods to plug in to the extension points.
An extension point is characterized by:

An ID with which it can be referenced.

A GWT widget that wraps the extension functionality.
You can find the sample code for defining the extension points in the file ExtensionViewFactory.java that is provided in the demos folder under the CentraSite installation folder.