I trying to use 
fix_nated_sdp with 0x02 and 0x08 flags for changing ip addres and the SDP body part

like 

fix_nated_sdp(10,"1.2.3.4")

But for now it beaks SDP
At the output i see next

o=- 7300689428214760503 2 IN IP4 1.1.1.1
c=IN IP4 1.1.1.1
1.2.3.41.2.3.4   <- is just a line that added after fix_nated_sdp  atthe end of SDP body

kamailio -v
version: kamailio 4.4.3 (x86_64/linux) e91aec
flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
id: e91aec
compiled on 07:26:14 Oct 18 2016 with gcc 4.9.2