Can i send a message in a existing conversation established by two normal Lync user using UCMA 3.0/4.0?

Hi guys,

         Here is the scenario of my question:

                   There is a Two-party call between Roger and Regina, they are common Lync user. and they have send several IMs to each other. Now I would like to send a message(like a notification ) to them in their conversation window, but not open a new conversation window which contain the message I send to them.

         Here is my effort:

                   First, I read Michael Greenlee’s blog “Invisible OCS conference participants”, then I try to achieve my goal in that way. But it seems the Result is not what I want.

                   (1) This is “group conversation ”, but not conversation just between two normal Lync user;

                   (2) when the invisible application endpoint send a message in the “group conversation window”, it will not invisible now.

         So, can anybody give me some advice, I really appreciate that.

BR

Rainbow Zhou