It is recommended to have string values for enums in serialized/deserialized requests. but if you want an int value, then try using the XmlEnum attribute on the enums.
public enum AmenityCode
{
[XmlEnum("1")]
AirConditioning = 1,
[XmlEnum("2")]
AirportTranfer = 2
}
there is also a way to create shimmed properties, but that gets too messy when many properties are involved.