Accessing Interactive PDF Object Data?

I can create interactive PDF checkboxes and comboboxes, etc. using the "Buttons and Forms" panel, but I'm having trouble accessing this information in my InDesign plug-in. I can get the Actions list from the <IBehaviorList> interface, but I can't figure out how to get things like the list items from a combobox or most other information. All the other supported interfaces don't seem to give me anything I want.

Does anyone have any experience with this? Thanks for any info.

Bob