Access Point APX 530 does not work with Sophos XGS 136

Hi experts. I recently buy two new devices, Sophos FW XGS 136 appliance and AP530 wireless Access point. I am trying to put them to work togheter but not having success. I have registered I can manege Firewall va Sophos Portal, also same as AP (when it is connected to my LAN with a Internet access). However, when I connect sophos AP to firewall port, it does not appear in the AP list (PROTECT -> WIRELESS -> ACCESS POINTS), So I am unable to namage AP throught the Firewall. My scenario is as below:

Sophos XGS 136 Firewall PORT2 (WAN) connected to my Internet link and working fine

Port3 of Firewall configured as WiFi port, with DHCP actived and working fine

Alcatel-Lucent PoE Switch connected to FW Port3

Sophos APX 530 connected to PoE Switch and working fine (getting IPv4 address from DHCP on FW Port3

PROBLEM: AP does not appear in Access Points list (PROTECT -> WIRELESS -> ACCESS POINTS).

Active/inactive access points: No records found

Pending access points: No records found

Any help will be welcome.