Application endpoint to Lync client conferencing

Hi All,

I am developing an application endpoint which starts conversation with Microsoft Lync Client 2010. we are using Lync Server 2013 and UCMA 4.0.

I am able to starts conversations and send message between my application and lync client. So two party

two-way communication works fine.

Now I am trying to send a message from (appendpoint) to lync client (user1) , which can invite other lync client(user2) to join the conversation, this raises conversation to conference escalation and my app endpoint received notification and my app endpoint joins the conference. Although, the user2 who is logged into lync client and available never receives any invitation.

So I can see my application end point and user1 in the conference , but user2 never receives any invitation and thus not present in the conference.

As per my understanding, since the lync client is one escalating to conference, another lync client should get an invitation and decides to join or ignore? 

Can someone please tell me what am I missing? 

Since user1 and user2 are logged into lync client, I dont have any control over that.