How to insert a Reading Passage into a Diagram-labelling Bookwidget task

Bookwidget's Split Tasksheet format does not allow users to put a reading text on one side, and insert another created Bookwidget (in this case, 'Diagram Labelling') into the right. 

This is a workaround that have found out. 

I simply opened the created Diagram Labelling bookwidget (in this case: 'Layers of a Forest'). In the Question box, I inserted the passage itself. (In my workaround, I simply got a screenshot of the passage, and pasted it into the Question box which I switched to RTF).