In order to send unicode offline message, we can modify the method getOfflineMsg of the class  
net.sf.jml.protocol.soap.OIM as follow. 
 
private String getOfflineMsg(Email email, String txt) 
{ 
StringBuilder mess = new StringBuilder(); 
String displayName=new String(); 
try 
{ 
displayName=new String(Base64.encode(session.getMessenger().getOwner().getDisplayName().getBytes("UTF-8"))); 
txt=new String(Base64.encode(txt.getBytes("UTF-8"))); 
} 
catch (UnsupportedEncodingException uee) 
{ 
    uee.printStackTrace(); 
} 
mess.append("<?xml version="1.0" encoding="utf-8"?>rn"); 
mess.append("<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"rn xmlns:xsd="http://www.w3.org/2001/XMLSchema"rn xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" >"); 
mess.append(" <soap:Header>"); 
 
mess.append(" <From memberName="" + session.getMessenger().getOwner().getEmail().getEmailAddress() 
+ "" friendlyName="=?utf-8?B?" + displayName + "?="rn xml:lang="nl-nl"rn proxy="MSNMSGR"rn xmlns="http://messenger.msn.com/ws/2004/09/oim/"rn msnpVer="MSNP15"rn buildVer="8.5.1288.816"/>"); 
mess.append(" <To memberName=""+ email.getEmailAddress() + "" xmlns="http://messenger.msn.com/ws/2004/09/oim/"/>"); 
mess.append(" <Ticket passport="" + sso.getOimTicket().replaceAll("&", "&amp;") + ""rn appid="PROD0119GSJUC$18"rn lockkey="" + lockkey + ""rn xmlns="http://messenger.msn.com/ws/2004/09/oim/"/>"); 
mess.append(" <Sequence xmlns="http://schemas.xmlsoap.org/ws/2003/03/rm">rn"); 
mess.append(" <Identifier xmlns="http://schemas.xmlsoap.org/ws/2002/07/utility">http://messenger.msn.com</Identifier>rn"); 
mess.append(" <MessageNumber>" + sentMsgNumber + "</MessageNumber>rn"); 
mess.append(" </Sequence>rn"); 
mess.append(" </soap:Header>rn"); 
mess.append(" <soap:Body>rn"); 
mess.append(" <MessageType xmlns="http://messenger.msn.com/ws/2004/09/oim/">text</MessageType>rn"); 
mess.append(" <Content xmlns="http://messenger.msn.com/ws/2004/09/oim/">MIME-Version: 1.0rn"); 
mess.append("Content-Type: text/plain; charset=UTF-8rn"); 
mess.append("Content-Transfer-Encoding: base64rn"); 
mess.append("X-OIM-Message-Type: OfflineMessagern"); 
mess.append("X-OIM-Run-Id: {3A3BE82C-684D-4F4F-8005-CBE8D4F82BAD}rn"); 
mess.append("X-OIM-Sequence-Num: " + sentMsgNumber + "rnrn"); 
mess.append(" " + txt + ""); 
mess.append(" </Content>"); 
 
mess.append(" </soap:Body>"); 
mess.append("</soap:Envelope>"); 
 
return mess.toString(); 
}