I tried to modify the position of an airport with WED, because the default airport is no aligned with the photoscenery. I created a geoTIF with this tool: http://www.allmapsoft.com/gsmd/

 

But when i load it into WED its not at the right place. What am I doing wrong? Any other source for geoTIF in Europe?

you can move it in WED. I found that when I created a couple of New Zealand airports they were not in the right place by miles. So I extended the runway to 50 miles and then by going in and out of WED and X-P i was able to position it in the right place. It was just trial and error but it worked.