Hi Stuart,
There's no automated way to do this yet, however for basic designs there's a simple workaround you can use: basically you have to place the text inside a shape to use it as a frame for the text with the Frame Text tool. However before you do this you have to create a rectangle shape a little bigger than the image you want to use (it will serve to add a margin around the text - in the attached image below it's the equivalent to the blue circle) and subtract it from the main shape (the green rectangle in the screenshot below). Then with the resulting shape still selected, place the Frame Text tool over it (the cursor will change to a "T" inside a polygon) and click to fill it with text or paste you text there.