Sophos NextG Web Application Firewall for Exchange with Multi-Factor Authentication (MFA)

Hi All, 

Due to EOL with Sophos UTM 9,  We recently upgrade to Sophos Next Gen Firewall.

We used to have a feature with Sophos UTM that allow to enabled OTP / Multi-Factor Authentication on Web Application Firewall or Web Application Proxy for second authentication to web servers from the outside world such as MS Exchange Server Webmail or ActiveSync.   This worked great! 

Now that we've moved to Sophos Next Gen,  we are not able to see or identify on how we can do an like for like configuration.  

I have looked at Article below but can not see anything about MFA  

support.sophos.com/.../KB-000040209

Has anyone does this before or came up with an alternative solution? 

Thanks

John