Custom renewal of SharedAccessSignature

Hi,

We are trying to receive messages from a 3rd party system that provides us with a Service Bus connection string including a SharedAccessSignature.

This SharedAccessSignature expires every 4 hours so we need to renew it from this 3rd party's custom HTTP GET endpoint; we don't have access to the Azure account.

How can we extend the ClientSettings / TokenProvider to use this custom implementation to refresh the authentication?

Thanks