handler.setBeanLookupExpression("lookupMap");
handler.setBeanPropertyName("domainClass");
handler.setBeanPropertyClass(Integer.class);
handler.setConversionHandler(new DefaultConversionHandler());
Converter converter = new StandardBeanUtilsConverter();
handler.setConverter(converter);
converter.setTargetClass(Integer.class);
// needed for binding outwards
PropertyDescriptor propertyDescriptor = PropertyUtils.getPropertyDescriptor(new BindableBean(), "selectedId");
handler.setPropertyDescriptor(propertyDescriptor);