You have replaced the referenced texture in your material so panda loads up the earth texture. You only need to copy the material settings to your material.
<Texture> Tex6815 {
shirt.jpg // This is the image file applied to the material
<Scalar> format { rgba }
<Scalar> wrapu { repeat }
<Scalar> wrapv { repeat }
<Scalar> minfilter { linear_mipmap_linear }
<Scalar> magfilter { linear }
<Scalar> envtype { modulate_gloss }
}That would work with the original egg file you generated, if not just change the material name to the one in your TRef.