But the thing is it is not working in this ad-on scenery!
Well, that's nothing GSX could help with...we'll likely add a feature to let user add one of the several FSDT (working) docking systems in a scenery that doesn't have them, but the issue is, if you have a scenery with a non-working one, it could be very difficult to remove it.
Because putting him in front of the pole I am not sure I can see him at that position from the cockpit?
Well, of course that's an issue, since the position calculated by GSX, is related to your eyepoint. But sometimes, because of the scenery constraint, you must reduce it. Perhaps you should use the key to raise your eyepoint in the VC.
And that post has the (Visual Docking System?) on it see picture!
Ok, it's not that, when they install a VDGS, they fire all the Marshallers. Perhaps it was out of order that day...but maybe on THAT airport, you have enough space to place a marshaller in front of the post and still see him from the cockpit, but you might not have it at your scenery.
Moving the Marshaller left/right is wrong: he must be perfectly aligned with the yellow line, otherwise it would be very difficult to judge (for you and for him) the lateral distance to give you signals.