Custom SMS gateway integration for Passwordless

Hi All, I would like to integrate a custom sms gateway with Auth0 for passwordless. I see quite a few documentation for SMS based MFA via the hooks supporting multiple 3rd party gateways but not for passwordless connection. We have a custom SMS gateway that creates a signature for authenticating the api call based on api key and secret. Is this supported by having “gateway_authentication” object or we need to implement a custom proxy redirecting to a lambda function like it was described in the link below: inhttps://community.auth0.com/t/how-to-use-aws-sns-for-sending-sms-for-passwordless/72763