[Serusers] Instant Messaging User Agent Interoperability problem

Hi all, I am testing the Instant Message Service with the SER v0.8.14 and I see that it routes them correctly towards the destination user agent. However, what I have seen is a tremendous imcompatibility between user agents of different vendors. Here just a bit of this: IM between two Windows Messenger 4.7. What I see it that the very first MESSAGE in the conversation is sent towards the SER and it routes it perfectly but the subsequent MESSAGES are exchange between both Messengers directly!!! It is weird... but this is how it is working. IM between Window Messenger 4.7 and EyeBeam v1.1 The EyeBeam always send the MESSAGES towards the SIP proxy and messenger receive them with no problem. However, when the messenger tries to send a MESSAGE in the conversation it even doesn't send the packet (I tried to capture it with Ethereal and no packet was sent at all) and subsequently tell you that the text message could not be delivered to the destination. IM between EyeBeam v1.1 No problem at all. IM involving Windows Messenger 5.1 This version of messenger sends an INVITE to the destination before issuing the MESSAGE. With EyeBeam is a total disaster and the comunication is not possible. My conclusion is that the SER has not implication in such incompatibility at all and that is a matter of interoperability among vendors and different implementations of SIMPLE. Do you agree? Thanks in advance Victor