pjsip

Just quoting the OP as he found the solution, but forgot to add it as an answer: Edit: I found the solution thanks to a co-worker: struct pjsip_generic_string_hdr CustomHeader; pj_str_t name = pj_str(“MyHeader”); pj_str_t value = pj_str(“HeaderValue”); pjsip_generic_string_hdr_init2(&CustomHeader, &name, &value); pj_list_push_back(&cfg.reg_hdr_list, &CustomHeader); This seems to work as expected.