Object doesn't appear to have PropertySets

[jr-accurate]

Hi,
I'm having issues reading PropertySets of some IfcProduct. In my BIM viewer it seems like there are PropertySets defined, however the IfcProduct.getIsDefinedBy()-relation seems to be empty.
Here's roughly what I'm doing:

// get IfcProducts of a certain storey
for (IfcRelContainedInSpatialStructure containsRel : storey.getContainsElements()) {
            for (IfcProduct ifcProduct : containsRel.getRelatedElements()) {
                        // for the product, get it's PSets
                        for(IfcRelDefinesByProperties rel : ifcProduct.getIsDefinedBy()){
                                    IfcPropertySetDefinitionSelect set  = rel.getRelatingPropertyDefinition();
                        }
            }
}

I'm trying to read this file: http://www.ifcwiki.org/index.php?title=File:AC20-Institute-Var-2.ifc

Basically I want to figure out if a door is external. Now I realize that Pset_DoorCommon isn't set, but some custom ArchiCad-specific sets seem to be in the file, so I think I should be finding something.

Any idea on what I'm doing wrong?