[Serusers] how does cpl proxy handle ACK?

Hi, In my ser script, I call cpl_run_script("incoming", "force_stateful"). With the following cpl script, I can't handle ACK well. So ser keeps sending 200 OK to the caller. I called t_newtran() for ACK but doesn't seem to have effect. The ser debug is as follows. Thanks, Richard ===== cpl script =============== <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE cpl PUBLIC '-//IETF//DTD RFCxxxx CPL 1.0//EN' 'cpl.dtd'> <cpl> <incoming> <location url="sip:ivr+3560073@o-matrix.net"> <proxy /> </location> </incoming> </cpl> ======= ser log on ACK t_newtran 0(841) About to create new transaction 0(841) DEBUG: t_newtran: msg id=135 , global msg id=134 , T on entrance=0xffffffff 0(841) parse_headers: flags=-1 0(841) parse_headers: flags=60 0(841) t_lookup_request: start searching: hash=33036, isACK=1 0(841) parse_headers: flags=28 0(841) DEBUG: t_lookup_request: e2e proxy ACK found 0(841) parse_headers: flags=4 0(841) DEBUG: totag for e2e ACK found: 0 0(841) DBG: trans=0x402ecb88, callback type 4, id 0 entered 0(841) parse_headers: flags=44 0(841) ACC: request acknowledged: call_id=4b75e616-2670ed04-f3c2ee41(a)192.168.5.85, totag=00006D4834BCB620, from="3560076" <sip:3560076@o-matrix.org>;tag=EF7F5BC3-7D34BC88, i-uri=sip:ivr+3560073@66.175.65.80, method=ACK, o-uri=sip:3560073@66.175.65.80, fromtag=EF7F5BC3-7D34BC88, code=200, to=<sip:3560073@o-matrix.org>;tag=00006D4834BCB620, uid=n/a, userpart=ivr+3560073 0(841) parse_headers: flags=44 0(841) XLOG: xl_print_log: final buffer length 31 0(841) About to send to a sems module 0(841) receive_msg: cleaning up __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - 100MB free storage! http://promotions.yahoo.com/new_mail