I'm not entirely sure what you are asking. Why you think you have to disable GSX ? Since GSX was released, it always worked in every airport you use, and will read the data from the scenery AFCAD that comes with the airport.
Of course, you might still want to customize it, to fine tune vehicle positions, etc. but, in general, everything will work.
In addition to that, I think the new Koln scenery already comes with SODE jetways so, there's no replacement to be done either.