// extending complex type with simple content
SimpleExtension se = ct.simpleContent().extension();
contentModel = se;
se.base(bc.getTypeName());
} else {
ComplexExtension ce = ct.complexContent().extension();
contentModel = ce;
ce.base(bc.getTypeName());
// TODO: what if the base type is anonymous?
// ordered props go in a sequence, unordered go in an all