Lync for Mac crashes on receiving context

We are developing Lync integrated applications that send context information along with the conversation. When such a conversation is received by a Lync client on the Mac (14.0.4 now), that Lync client immediately and systematically crashes.

This makes our task very difficult, since before the call is answered we cannot know that the other client is a Mac client.

Are there any people out there who have experience with sending context on calls that might be received by Mac clients?

Thanks for your help,

Pierre