My guess would be to look through Dragon's Waffen-SS sets... That pattern was strictly a Waffen-SS thing and although some Heer uniforms were made in it, it wasn't very common for Heer troops to have it...
The Waffen-SS had its own uniform R & D section and any of the M-44 uniformed troopsets can be painted in that pattern, as well as the ones in pull-over smocks, as well as the Panzer crew uniforms... During the Ardennes Offensive though, there would likely be a mix of regular uniforms with overwhites and reversable winter uniforms... You can find decal material to make the Pea Dot pattern, but it's more likely that you'llbe doing the painting... Manny is kinda the "Camo-god" for SS troops around here, so perhaps you could pull him away from painting cleavage and bend his ear a bit...
Here's some research starting points:
http://images.google.com/images?gbv=2&hl=en&q=pea+dot+camo&sa=N&start=40&ndsp=20
http://images.google.com/images?q=Waffen-SS+winter+uniforms&btnG=Search+images&gbv=2&hl=en&sa=2&start=0