Technically, you don't even have to attempt to start the car to be charged with DUI. If you have the keys, and get into the car while intoxicated, you can be cited.
In the case you describe, I would expect a defense attorney to claim that because of the interlock device, you did not have the means to start the engine, and that is grounds to dismiss the charge. I am not aware of any cases where a court has actually ruled on the issue.
As davidni711 stated, even if it isn't DUI, it most likely IS a violation of the terms that require the interlock to be installed.
By the way, in the multiple times you have asked, has anyone pointed out that the unit in the car is legally admissible evidence you were intoxicated, and ATTEMPTED to drive?