that's great that You have connections to Germany! I've sent You a PM.
My H. pinnatifida photo on the "Aqua Planta" cover is a little too much "doctored", the plants actually don't look this red (however, the underside of the submersed leaves is pink.) The last photo in my article isn't from me, I wonder who contributed it.
@Martin: fine, it's growing also in Denmark
I think this Hygro will become more common in the hobby.
It propagates mainly by creeping, runner-like stems, developing on the lower nodes of upright stems.