Harmony Hub with Hue Emulation - cannot pair

Is there any trick to have the harmony hub find my openhab server?
I have the Hub and all other devices on two different vlans.
Actually the Logitech app finds the real Hue Bridge (it seems) and presents the pairing screen, yet does not show the second emulated bridge.

Ok, should have tested it first.
hub and openhab need to be on the same lan segment/vlan.
hub then found openhab and emulated bridge immediately. after putting the hub back into the other vlan, the connection remains as it is obviouslynonly dependent on the ip adress.