Slow,
The gust speed is not a significant contributer to the helicopter's load factor, I think, unlike starched wings, where the wing loading allows some real load factor to be generated by the gust.
Its a simple velocity match. If a common airplane with normal wing loading (maybe 20 lbs/ft2) and cruising at 120 knots (200 feet per second) experiences a 50 ft/sec gust, there is a very real shift in the angle of attack (the angle of the new speed vector has a tangent of 50/200, or a 14 degree angle of attack change!)
For a helicopter, the blade loading is in the order of 75 to 100 lbs/ft2, and the average blade speed is about 350 feet per second, so the resulting angle of attack change is smaller, and the net change in lift is also smaller.
The AD on gusts is really a limitation for new pilots only, and seems to control the possible overcontrol hich might lead to mast bumping. This has more to do with the pitch axis re-trim in the gust than it does with load factor, I'll wage:
http://www.airweb.faa.gov/Regulatory...D?OpenDocument