This document registers new disposition-types for the Content- Disposition header that apply to the application/3gpp-ims+xml body used by 3GPP, since Release 5. The applicability of these content- disposition values are limited to 3GPP IMS. The application/ 3gpp-ims+xml body has the following two distinct uses: (1) for redirecting the emergency session to use a different domain (e.g. using a Circuit Switched call), and (2) for delivering user profile specific information from the SIP registrar to an Application Server.