Well finaly I found two way's to fit the disc to the sphere.
Here is the top view.

As you can see I devided the disc in two piecesI.
I created a box (Ion engine) to give extra support on the wing.
In the box I mounted a 6 mm thick paper tube that fits in the sphere.
This also give's extra support to the disc.
I have to make some small adjustment's on the box to make it easier to mount the tube.
Side view disc glued directly on wing support. (left side)

And the disc mounted thru the wing support. (Right side)
Sorry for the bad shape off the wing support. I had to remove the wing to cut in the wing support.

I think I gone use the last option because I don't get a gap between disc and wing support.
Also I can make better adjustment's between the disc and the sphere.
Now I have to find a way to keep the shape of the wing support when I attach the disc.
Maybe I gone use some small strip's that I mount on the wing support.
And I cut these strips when the wing support is fitted on the sphere.
If I bent the cutted support I can use that as a tab and glue the disc on it.
Next step is to create a strong joint between the wing ande the wing support.
Hope to see you all with the next update.