masking text3D

[mojtaba tabatabaie]

hi , I have a text3D and I want to mask it with a Plane . I usually mask my
things by defining two ViewportLayers , then give every object a Layer by
myLayer1 = viewport.getChildLayer(myobject1);
myLayer2 = viewport.getChildLayer(myobject2);
and then mask it by
myLayer1.mask = myLayer2;
and it works , but when I try to mask a text3D object it doesn't work at all!
anyone has any experience with it ?
thanks