[Serusers] t_uac_dlg pb

I want to send an invite request to ser's fifo using t_uac_dlg command and exec_msg, my pb is that i can't construct a valid invite header , when i check the log of ser, i see that there is errors in parsing headers. i'm trying to send something like this : cat > /tmp/ser_fifo << EOF :t_uac_dlg:hh INVITE sip: user2(a)sip.server.net . From: sip:user1@sip.server.net To: sip:user2@sip.server.net . Content-Type: application/sdp EOF please can someone correct it. Regards PS : the valid header is the following : Session Initiation Protocol Request-Line: INVITE sip:5001@sip.softiphone.net SIP/2.0 Message Header Via: SIP/2.0/UDP 192.168.1.100;branch=z9hG4bK52ffa6c1cda5b285 From: "5003" <sip:5003@sip.softiphone.net>;tag=81ee9e99dc30cc34 SIP Display info: "5003" SIP from address: sip:5003@sip.softiphone.net SIP tag: 81ee9e99dc30cc34 To: <sip:5001@sip.softiphone.net> SIP to address: sip:5001@sip.softiphone.net Contact: <sip:5003@192.168.1.100> Supported: replaces, timer Call-ID: b2d776f6e99851a4(a)192.168.1.100 CSeq: 44559 INVITE User-Agent: Grandstream GXP2000 1.0.1.9 Max-Forwards: 70 Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDATE,PRACK Content-Type: application/sdp Content-Length: 310 Message body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): 5003 8000 8000 IN IP4 192.168.1.100 Session Name (s): SIP Call Connection Information (c): IN IP4 192.168.1.100 Time Description, active time (t): 0 0 Media Description, name and address (m): audio 5004 RTP/AVP 0 8 18 3 4 101 Media Attribute (a): sendrecv Media Attribute (a): rtpmap:0 PCMU/8000 Media Attribute (a): rtpmap:8 PCMA/8000 Media Attribute (a): rtpmap:18 G729/8000 Media Attribute (a): rtpmap:3 GSM/8000 Media Attribute (a): rtpmap:4 G723/8000 Media Attribute (a): ptime:20 Media Attribute (a): rtpmap:101 telephone-event/8000 Media Attribute (a): fmtp:101 0-11