[Bloerb]

I want to monitor some field values and write them out.
I created a volScalarField for that purpose

    Info<< "Reading field myField\n" << endl;
    volScalarField myField
    (
        IOobject
        (
            "myField",
            runTime.timeName(),
            mesh,
            IOobject::READ_IF_PRESENT,
            IOobject::AUTO_WRITE
        ),
        fieldA*fieldB
    );

And have a line inside my solver loop to set the values

 myField = fieldA*fieldB

I also want to set the boundary values of this field. The boundary should have the normal gradients of both fields multiplied with each other. I think i have to use myField.boundaryField() but how do I set it to equal fvc::snGrad(field1) & snGrad(field2) ?
I have no clue as to how to do this.