compile problems using generic wrapper templates with inherited method templates

I'm using the generic wrappers and trying to use the inherited methods template example to register base class methods for derived classes. I get the following compile error when changing from asMETHOD to WRAP_MFN in the RegisterBaseMembers<> template:

error: invalid operands of types ‘<unresolved overloaded function type>’ and 'bool (MotorControl::*)()' to binary ‘operator<’

Called from:

RegisterBaseMembers<MotorControl>(engine, “MotorControl”);

In template:

template <class T> void RegisterBaseMembers(asIScriptEngine* engine, const char type)
{
    r = engine→RegisterObjectMethod(type, “bool isOn()”, WRAP_MFN(T, isOn), asCALL_GENERIC); 
                                                         ^ // ERROR
}

But, the following template compiles fine (with asMETHOD instead of WRAP_MFN):

template <class T> void RegisterBaseMembers(asIScriptEngine* engine …