Hi James,
I see how my explanation might be unclear.
We have a main form for the agenda and a subform for an item, which is shown using Seaside call/answer. The save button of the subform is clicked, which adds the item to the underlying agenda model object, but the save button of the main form is not clicked by the user. The callback for the main save button sends the save message to the agenda object, causing the database to be updated.
So yes, the browser does submit the data on the subform, it's the main form component that doesn't receive the save button callback. I realize that this is in large part an issue with our design. However, the way object persistence seems to work in the image environment plays a large role.