[Freeswitch-users] Adding headers to provisional responses

Hi, I am trying to add a header to my responses according to this: http://wiki.freeswitch.org/wiki/Sofia-SIP#Adding_Response_Headers When I add a sip_rh_ header, it appears fine in my 200 OK response. However, when I try to add a sip_ph_ header, it does not appear in the 100 Trying response. Am I doing something wrong or is there a bug?