OK, Have not flown the R-22 in many years, but just checked a manual. I stand somewhat corrected. An addendum to the Normal Procedures section, issued per FAA AD95-26-04 talks about mast bumping among other things.
I quote in part:
"pilots are strongly urged to follow these recomendations:
3)Avoid sideslip during flight. Maintain in-trim flight at all times."
This does still not prohibit sideways flight above 17kts.