Keith is listed in the credits, all the way down on the bottom. There is also a picture of him and Anita on the set, I think it can be found on the Anita Pallenberg multiply site.
Full cast and crew for Michael Kohlhaas - Der Rebell (1969)
Directed by:
Volker Schlöndorff
Writing credits
(in alphabetical order)
Edward Bond adaptation
Volker Schlöndorff writer
Heinrich von Kleist novel "Michael Kohlhaas"
Clement Biddle Wood writer
Cast (in credits order)
David Warner ... Michael Kohlhaas
Anna Karina ... Elisabeth Kohlhaas
Thomas Holtzmann ... Martin Luther
Michael Gothard ... John
Kurt Meisel ... Kanzler
Anton Diffring ... Kurfürst
Gregor von Rezzori ... Kunz
Peter Weiss ... Richter (as Peter Weiß)
Anita Pallenberg ... Katrina - Marketenderin
Relja Basic ... Nagel (as Relia Basic)
Inigo Jackson ... Wenzel von Tronka
Václav Lohniský ... Herse
Anthony May ... Peter
Tim Ray ... Tony
Ivan Palúch ... Stern (as Ivan Palluch)
Emanuel Schmied ... Verwalter
Erich Aberle ... Bürgermeister
Zdenek Kryzánek ... 1. Jurist
Karel Krisanek ... 2. Jurist
rest of cast listed alphabetically:
Hanna Axmann-Rezzori
Nadia Kotrosova
Mikulás Ladizinský (as Michael Kadisinski)
Osman Ragheb
Enzio von Rezzori
Maurice Warner
Keith Richards ... Soldat (uncredited)[
www.imdb.com]