You do not need to multiply the manufacturer's power curve by the wind probability.  Just enter the true power curve showing the turbine's power output versus wind speed.  Every hour of the year, HOMER will calculate the output of the wind turbine that hour based on the wind speed that hour.

If the wind resource was measured at a different height than the wind turbine's hub height, you can adjust the wind speed using the wind speed scaling factor on the Wind Turbine Inputs window.  For example, if the wind resource was measured at 10m above ground and the hub height of the wind turbine is 25m, and you want to use a power law exponent of 0.14, enter (25/10)^0.14 = 1.137 for the wind speed scaling factor.