If you already have fog lamps then the Ring Aurora will fit in the steps, but personally I don't like that idea because it allows much and dirt to get trapped behind as they are not flush and look a bit chavy in my opinion. A member here posted a cowel he made to go around - search for DRL - I think I started that thread.
Hella do some with a flush mount which removes the step and fits a plate around the lamp which can be painted, but these are around €200 - search Ducato DRL on ebay.de or google.de.
There are also a couple of other kits specifically for the Ducato - one which fits in place of the lower headlamp surround and gives 6 or so forward facing LED's.
I'm pretty sure that DRL's should dim when the headlamps are in use so check that the kit does so.