String callid=sip_provider.pickCallId();
int cseq=SipProvider.pickInitialCSeq();
String localtag=SipProvider.pickTag();
//String branch=SipStack.pickBranch();
Message req=createRequest(sip_provider,SipMethods.MESSAGE,request_uri,recipient,from,null,callid,cseq,localtag,null,null,null);
if (subject!=null) req.setSubjectHeader(new SubjectHeader(subject));
req.setBody(type,body);
return req;
}