My friend, COL Jim purchaed this book World War II Battlefield Communications from the Osprey Elite series by Gordon Rottman and Peter Dennis.
The book had a photo of a US Duwk that had a commo box in the back. I never saw this before but it made sense so I quickly whipped one up and used the Duwk I got at the recent kit show. Just cut down the back end of the canopy, and add a Roco radio box. A quick, easy conversion.