It is possible, but with manual configuration. Mikrotik is ignoring our requests to implement "AP/switch" type of quickset profile. Perhaps you can do users coming behind you a favour and open support ticket with request for such option.
The steps are the following:
- forget about quickset from this point forward. Don't ever set anything in quickset, it'll screw your config
- download winbox, you'll need it in steps further down
- connect to device, reset configuration with no defaults
- after device reboots, start up winbox. When it discovers device, click on its MAC address to connect
- create new bridge, add all interfaces as bridge ports. Don't add port "all", instead add each of interfaces one by one (including wireless interfaces)
- configure DHCP client - bind it to bridge interface. Verify that device indeed received IP address from existing LAN router
- set administrator's password (if you weren't forced to do it in step #3 above)
- configure wireless interfaces - SSID, PSK, etc.
You can decide to exit winbox after completing step #7 and proceed via web browser, but steps between #3 and #6 (inclusive) can only be done using winbox because it can connect to ROS device without having a valid IP address.