Messenger SendText Problem

Hi Everyone,

I have a module which i have been working for the past couplr of days.
I am trying to send im from my ap thru Messenger Type Library.
(Windows Messenger, .Net 2.0 anf Messenger Type Library 1.0)
I have two services, .Net Messaging service for hotmail and SIP
communication service for company im)

and i have the following code

Messenger.MsgrObject objmsgr = new Messenger.MsgrObject();
string header = "Mime-Version: 1.0\r\nContent-Type: text/plain;
charset=ASCII\r\n\r\n";

IMsgrUser2 contact =
(IMsgrUser2)objmsgr.CreateUser(emailaddress,
objmsgr.Services.PrimaryService );

contact.SendText(header, "pk here", MMSGTYPE.MMSGTYPE_ALL_RESULTS );


Now if i use .Net Messaging service, i am able to send a message but
when i use sip communications service, the sendtext method throws an
exception saying "The moethod or operation is not implemented"

Any help on this is appreciated!

Thanks,
PK