NIST-SIP Specific support for IMS headers contributed by Jose Miguel Freitas (Aveiro University, Portugal) and Alexandre Miguel Silva Santos (PT Inovacau, Portugal). It is not part of the JAIN-SIP 1.2 specification. Questions about the IMS Support in NIST-SIP 1.2 can be directed to Miguel Feitas or the NIST-SIP mailing list. To acccess these headers you have to cast the HeaderFactory to HeaderFactoryImpl. This package has been contributed to the public domain.