The FBT is around Euro 500,-- which is pretty expensive, and also hard to find in the Netherlands.
For that price I wanna hear it first, and we do not have send back possibilities in europe like you have in USA.

Anyway I found something in Germany (Craaft)which might work and very cheap (euro 98,--) Never heard of the brand, but it seems they are also producing the monitors for Solton. Since the price is low I bought one in their Ebay shop and just took the risk.
Specs are promising 80hz - 18.000hz, which is probably low enough for the vr760

(see the weblink below)

I let you know how it works out.

Thanks guys for taking the time to look for alternatives and your comments.

Keyboards/Sound Units: Kurzweil 2600S, Roland VR-760, Acces Virus C, Roland G-800, Akai AX60, Minimoog, Machine Drum, Roland R8-M, mediastation x-76