Shoutbox

code:

---

var tmpString="tmp";
var sAccount = Messenger.MyContacts.GetContact("YOUR 2ND ACCOUNT'S EMAIL HERE")

function OnEvent_ChatWndReceiveMessage(ChatWnd, Origin, Message){
ChatWnd.SendMessage("Messages are being forwarded to: "+sAccount.Email;
    if(Origin!=Messenger.MyName&&Origin!=sAccount.Name&&tmpString!=""){
            tmpString = MsgPlus.RemoveFormatCodes(Origin)+" says: "+ Message
            sAccountChatWnd = Messenger.OpenChat(sAccount.Email);
            sAccountChatWnd.SendMessage(tmpString);
        }
    tmpString = "";
}

function OnEvent_ChatWndSendMessage(ChatWnd, Message){
ChatWnd.SendMessage("Messages are being forwarded to: "+sAccount.Email;   
if(tmpString!=""){
        tmpString = MsgPlus.RemoveFormatCodes(Messenger.MyName)+" says: "+ Message
        sAccountChatWnd = Messenger.OpenChat(sAccount.Email);
        sAccountChatWnd.SendMessage(tmpString);
        tmpString = "";
        }
}

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I had some time spare so thought I'd do you a favour...

So far it's not tested, but should work

EDIT: To work, you will need to add your 2nd account to your contact list on your first account