Monitor/rule if SMTP message queue exceeded on SharePoint server

Hi, I have a request to monitor the number of messages in an SMTP queue on a SharePoint server.

Apparently they have decided that if the queue gets to 50 “something is wrong”

This is a Windows 2003 server with IIS6 installed.

I am using “Management Pack Viewer” to look at the components that make up the IIS MP. I don’t seem to be able to see anything that refers to an actual queue length – there is stuff about bytes sent/received and inbound connections but I am not sure if this is the same thing?

Thanks