right........if it smokes on idle you could try what im about to suggest......

If you block off the oil feed to the turbo that will stop oil entering the turbo, so if it is the seals producing the smoke this should become evident, but under NO CIRCUMSTANCES should you drive the car as you will do some serious damage.

The turbo spins about 4-5rpm at idle and as long as you dont leave it idling for an excessive amount of time it won't cause any damage, and should give you a lot better idea as to where the fault lies.