_validSubstitutions = new SequencedHashSet();
Collection eltProps = _propertyModelByElementName.values();
for (Iterator it = eltProps.iterator() ; it.hasNext() ; )
{
SchemaProperty prop = (SchemaProperty)it.next();
QName[] names = prop.acceptedNames();
for (int i = 0 ; i < names.length ; i++)
{
if (! _propertyModelByElementName.containsKey(names[i]))
_validSubstitutions.add(names[i]);
}