/* syntax:

	:t_uac:[file] EOL
	method EOL
	r-uri EOL 
	dst EOL 				// ("." if no outbound server used)
							// must be used with dialogs/lr
	<EOL separated HFs>+	// From and To must be present at least;
							// dialog-apps must include tag in From
 							// (an ephemeral is appended otherwise)
							// and supply CSeq/CallId
	.[EOL]
	[body] 
	.EOL


	there is also the possibility to have server placed its
    hostname:portnumber in header fields -- just put double
	exclamation mark in any of the optional header fields
	(i.e., any but From/To/CallID,CSeq), they will be 
	substituted hn:pn

Example:

sc fifo t_uac_dlg MESSAGE sip:joe@192.168.2.1 \
	. \ # no outbound proxy
	'From:sender@iptel.org;tagd=123'  \ # no to-tag -> ephemeral
	'To:sender@iptel.org' \
	'Foo: sip:user@!! '  \ # expansion here
	'CSEQ: 11 MESSAGE   ' \
	. \ # EoH
	.	# empty body
---
U 192.168.2.16:5060 -> 192.168.2.1:5060
MESSAGE sip:joe@192.168.2.1 SIP/2.0..
Via: SIP/2.0/UDP 192.168.2.16;branch=z9hG4bK760c.922ea6a1.0..
To: sender@iptel.org..
From: sender@iptel.org;tagd=123;tag=5405e669bc2980663aed2624dc31396f-fa77..
CSeq: 11 MESSAGE..
Call-ID: e863bf56-22255@192.168.2.16..
Content-Length: 0..
User-Agent: Sip EXpress router (0.8.11pre4-tcp1-locking (i386/linux))..
Foo: sip:user@192.168.2.16:5060..
...


*/