Can direct media be established between primary and expansion sets
 

I've got a couple of phones set with 'direct media allowed' . Both register to the same IP Office. When I call between the phones, I can see on system Status, the call type is 'Direct Media' :)

However, when one phone is registered to the Main Office and the 2nd phone to the Expansion unit, the status is 'RTP Relay' .

My question is, should the two stations(on same subnet) be able to establish direct media in this scenario?
I cannot determine if its a config issue or whether this is normal behaviour when using a Primary and Expansion unit.

Does anyone know?

Are they connected with a Websocket SCN? Is direct path media enabled on the SCN line?