The conservative manner is to assume a gas only coefficient throughout. However, if you wish to be more accurate, the unit should be evaluated in the de-superheating regime (80%-100% humidity) and then using a wet surface coefficient for the remainder of the unit. 

The following articles discuss this topic:

Determination of apparent heat transfer coefficient by condensation in an industrial finned-tube heat exchanger: prediction

Experimental and computational performances of heat exchangers functioning in wet regime by using the film method.