Smartermail validate Mailbox Size at Inbound Gateway

Hello,

When use the SM as Inbound Gateway for another SM server does don't have the mailbox usage validation. With that, the Inbound Gateway Server still with a lot of messages at spool with the 421 mailbox full bounce.

I'd like to make the suggestion if the SM work as inbound Gateway for another SM to check the mailbox size and if it's full don't receive the message.