oil in the intercooler can only get their by 2 ways.. from the turbo, or from a breather pipe which is connected inbetween the air box and the turbo.
most breather pipes connect on the inlet pipe on the turbo.
you need to check if there is a breather pipe which is connected from the rocker cover to the turbo intake pipe...
obviously it will be connected before the turbo so that its sucking air out of your engine. it wont work is its connected on your boost pipe!
unless your getting large amounts of smoke at idle or when driving then its normal... to have oil in the intercooler, even more so if your always giving it some .....