Three-character language tag for the IDN domain that you're trying to register. This is only required for IDN domains.
Data required by the Registry for some country code top level domains (i.e. example.us).
In order to determine if a domain requires extended attributes, use [[SoftLayer_Dns_Domain_Registration::getExtendedAttributes|domain registration]] service.
The length of the registration period in years. Valid values are 1 – 10.