I would think that's the only way without major modifications. Unless the boost control is taken out of the control of the computer, there really isn't any way of tricking it into thinking the EGR is functioning properly....unless there's a way to trick it into thinking less air is flowing than there really is.
Maybe building a bypass of the airflow meter controlled by the EGR circuit would work. It would think EGR gas is flowing by the reduced amount of airflow through the sensor. And maybe dumping it back in pre-turbo would fool it enough. But then you have to deal with that blasted butterfly valve...
I don't have the time, money, or the will to modify my car to that extent to be the guinea pig for this experiment however
Edit: Geez, we thought of that at the same time...how weird
Edit again: And wouldn't an air breather tube post turbo just leak boost like crazy?