Sorry for delay. But according to doc for textops module: Set multipart body to a SIP message. If called with **no parameters, will convert present body** to multipart.
So if you have look at my part of CFG: 1. I use **set_body_multipart(,"2123894789_1257887457");** to convert Corrent current body with SDP to multipart. 2. then do **msg_apply_changes()** 3. next do **append_body_part_hex("01");** to append new part to current multipart body 4. do **msg_apply_changes()** to save changes into current message structure
It works normally in this way.