Does anyone have experience of the levels of compatibility between the 20S and the SRL2.

I have an SRL2 built into a Shoei helmet.  It is connected to my iPhone via bluetooth.  I have a friend who has a 20S and we have managed to get these two units to talk to each other, but i am unable to initiate a conversation on the SRL2, however he can initiate a connection with the 20S.

Today we were joined by a friend with a 20S EVO.  My friends were able to get the 20S and the 20S EVO talking by the usual pairing procedure (hold the centre button for 6 seconds until the leds flash red, tap the centre button).  However, I could not get the SRL2 to connect to the 20S EVO using the the same method (firmware 1.0.6 on the SRL2).  I would have thought that the SRL2 and the 20S EVO are compatible?  We wasted 30 minutes trying to get the 3 headsets to talk to each other, very frustrating....

As far as a "Group Conversation", I could not start this on the iphone app or the SRL2.  

Does anyone know if the SRL-2, 20S and 20s EVO are compatible?  If not, should I be using the "Universal Intercom" pairing procedure?