To define callout properties:
Click the callout frame, and then click the Properties 
icon on the toolbar to display the Properties pane on the right side of the main window. The Properties pane provides a variety of options for viewing and editing the HTML properties of the selected elements in the callout.
Some of the design features provided in Real-Time Designer can only be accessed from here. These are all standard HTML properties and can be modified accordingly.
The following sections describe many of the options in this area.