Exchange 2010 Hub Transport Rule

[MG_1878]

I have created a new Hub Transport ruleto reject all external mail with Zip files attached, and send a rejection message. The rule works in the sense that it is indeed rejecting all external mail with Zip files, but it is doing so silently & not sending the rejection mail. I know 99 out of 100 Zip files we receive are spam, so the rejection message isn't important, but for the odd occasion when the Zip file is legitimate I want the sender to know it hasn't reached its destination, rather than assuming we have received.

When I change the Transport Rule and set it for Internal mail, the bounce back message comes through to the sender absolutely fine...

 

I have read that it may be something to do with the Custom DSN Code, but when I go to the Exchange Management Shell and Get-SystemMessage, it all looks ok to me? It matches the DSN code with the message I want, and it says its set for external.

 

Just for info, I used the command... New-SystemMessage -DSNCode 5.7.11 -Text "custom message" -Internal $False -Language En

 

Anyone had a similar problem? Im hoping I have just missed something simple?

 

Kind Regards