Thanks for all your kind suggestions.
Perhaps a little clarification:
I'm not a real 'professional' but I'm fairly proficient with both Xara and Sketchup.
Off course always take into account that a person 'never' really knows 'all' the in and outs of a piece of software, things become even more complicated when you start using forementioned softwares in mixed situations - I often find myself trying to use Xara keyboard shortcuts in Sketchup and vice versa :-)

To the point:
I agree with doing the lot in Sketchup alone - but:
If I import the ground plan in my existing drawing (and yes, I realize it's mirrored - thanks for pointing out, but this is on purpose :-) ) the area on which I need to continue drawing is completely covered by the imported image.
That is my problem.

That's also why Xara jumped to my mind with it's transparency tool.
If such a tool would exist in Sketchup, I would be golden.
If I could enhance the image to be semi-transparent that would solve my problem.

Thanks again for your kind suggestions!

Erwin