Fill a 3.5 DetailView with design time demo data

I want to prototype a DetailView with data I manually put in my code just to demo the page.

I thought I could just build a public Dataset and design the Detail View using that, but you can no longer drag-and-drop a Dataset to a form, even if you have an .xsd file.

So, what I want to do is have my fields/tables in my dataset to match what WILL EVENTUALLY come from an actual database. And use this dataset to design the layout of the DetailView.