I have seen engine smoke many times in FS but I have never seen this before - it appears to be proper 'wake vortex' coming off the bits that jut out the back of the wings (not engine smoke that is usual).
I saw it on a flight today - EBBR to EDDF with the A320 - it was a little misty in Frankfurt and the sun was low.
Photo taken at 5000ft just after the U-turn point in the GPS transitions to runway 25. Was flying online, in FS2004.

Its not so clear anymore after resizing it and converting to jpg. But I can tell you that it was definately coming out here:

Where the arrows are.
Anyone else seen this (and don't get confused with the engine smoke

)