Dear Jerry,
After reading the previous post about the russo-german legion (thanks Rafa), it seems indeed they operated in the northern part of Germany as you've just written.
I've bought today a book on the abebooks website; it's about the second part of the 1813 campaign, and I hope to find further information on wallmoden'corp moves.
I'll let you know if you're interested in! I can read german, but the gothic style is sometimes very hard to decode...
All the best,
Pierre