To display content from the built in modules use the fluent API for the corresponding module in your rotator control.
is an example taking news items and adding an image from the images modules to the news item.
Custom modules can`t currently be accessed with the API. Custom modules add a frontend widget to display their functionality.
As a possible solution to get the content of a custom module in a widget is to use the custom module widget to get content from the built in modules.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items