Get vertex normal for creating morph by script

I would like to create an inflating morph by script (something similar to the push modifier)...

Creating a new morph is easy, but I don't know how to access to the vertex normals in order to use them into the morph...

var newMorphDeltas = new DzMorphDeltas();

var oNode = Scene.getPrimarySelection();

if( oNode ){

var oObject = oNode.getObject();

if( oObject ){

var oShape = oObject.getCurrentShape();

if( oShape ){

var oGeometry = oShape.getGeometry();

if( oGeometry ){

var nVerts = oGeometry.getNumVertices();

print(nVerts);

for( var i = 0; i < nVerts; i += 1 ){

newMorphDeltas.addDelta(i, ***, ***, ***, true);

print(newMorphDeltas.getDeltaVec (i));

}

}

}

}