[Serusers] SER/Asterisk 183 with SDP message

I am using Asterisk for IVR in conjunction with SER. My service provider prefers that I send a 183 progress message before sending a 200 OK, in response to their INVITE. I am using the "progressinband" option in sip.conf along with the Ringing() in extensions.conf for this purpose. When I set progressinband=no, Asterisk (i.e Ringing() command) sends a 100, followed by 180, followed by 200OK in response to an INVITE. However, when I set progressinband=yes, Asterisk sends a 100, followed by 180, followed by 183 (with SDP) followed by 200OK. I want asterisk to send only the 183 without the 180. i.e 100, followed by 183, followed by 200 OK, in response to an INVITE. How do I do that? regards, SCM