2002 Kx100 Water Pump Seal

This seal is "extra long/thick" compared to a normal oil seal. The seal looks about the same from either face but the steel frame around which the rubber is molded stops at half the thickness of the seal. The other half is all rubber with no steel sub-frame. What is the correct way to install this seal, "soft" side or "hard" side facing the water pump? My guess would be the soft side because the pressure from the hot coolant would expand the rubber more tightly around the pump drive shaft to prevent leakage into the crankcase. However, installation would be a bit more difficult because there wouldn't be a hard perimeter edge to push against. Anyway, I don't want to assume anything. Can anyone help? Thanx.

Rich Lee