this switchmove "EffectStandSitDown"
in the init field worked for me. If you're having trouble try deleting the unit and inserting a new one. Yes I know it shouldn't work, and it probably won't, but you never know.
Is he on the side of a hill? Does that make any difference? Or too close to a building?
The old animations are all listed in the Unofficial command ref in the Ed Depot. New (Resistance) ones are certainly in the forums, if not the Ed Depot.