Dear Sir/Madam

First please look image file in attachment.
We want the RBSXT device in customer side can connect to our Cisco PPPoE router.
Could you help me to which wireless mode we shall set on RB433AH & RBSXT device until PPPoE client on RBSXT can connect to our PPPoE router.

Best Regards

Just create a bridge and add the wlan interface and ether interface to the bridge.
use wireless mode station bridge on the client.