Retreive Normals from IGES reader

Hi,

I'm currently writing a converter that converts from IGES
into a Scene Graph Structure (OpenSG). I'm having some
trouble with the normals, most of them look ok but there
are always some corrupt normals (the file is ok as other
readers calculate correct normals!).

Here's more or less how I retreive the normals:

BRepGProp_Face prop(TopoDS::Face(child));

if( pc.Triangulation()->HasUVNodes() ){
for( int k = 1; k gp_Pnt2d uv = (pc.Triangulation()->UVNodes())(triangle(k));

gp_Pnt pnt;
gp_Vec faceNormal;

prop.Normal(uv.X(),uv.Y(),pnt,faceNormal);

if( TopoDS::Face(child).Orientation() == TopAbs_REVERSED )
faceNormal *= -1;
}
}

I observed that some normals are (0,0,0)... What am I supposed to
do with them?

And as I'm very new to the IGES format here some more questions:
Does the file format contain color information or the faces?
Does it contain Texture coordinates? Are the normals intended as
per vertex or do connected faces share the normals on
their shared vertices?

Thank you for your help, regards,

Toni