As far as I know no Russian Li-2's were taken in German service.
But I have in my collection a photo of a Li-2 showing signs that it was taken in German service.
The Russian red star has been wiped out and a German Eastern Front Yellow band has been painted on.
No other German markings (yet) but the presence of a Storch and the perfect condition of the Li-2 makes it possible that this is indeed a Li-2 taken in service by the Germans.
Jan