builder.recordBindingMode(ct, FALLBACK_CONTENT);
BIProperty prop = BIProperty.getCustomization(ct);
CPropertyInfo p;
if(contentType.asEmpty()!=null) {
p = prop.createValueProperty("Content",false,ct,CBuiltinLeafInfo.STRING,null);
} else {
RawTypeSet ts = RawTypeSetBuilder.build(contentType.asParticle(),false);
p = prop.createReferenceProperty("Content", false, ct, ts, true, false, true, false);
}