I haven't seen the particular aircraft up close .. however, many of the LE flow control devices launch a vortex which then, itself, interacts with the flow pattern further back along the chord to provide the desired effect.
There was a thread some time back dealing with large nacelle VGs (eg 737, 767) which do just this to delay the stall a few knots ... some of the thread hyperlinks were to quite good photographs which showed the shed vortex curling over the leading edge of the the wing very clearly. Perhaps you might like to search for that one and take a look for interest.
My guess, at this stage, would be that the devices to which you refer do much the same or, perhaps, are intended to improve aileron behaviour at low speed.
[ 29 December 2001: Message edited by: john_tullamarine ]</p>