I needed to make the Exchange Smarthost send mail via ASSP on a non standard port.
It is not possible to change the Smart host port using the graphical interface.
I had to use the Exchange Shell
Solution found here
http://forums.msexchange.org/m_1800467895/mpage_1/key_/tm.htm#1800467906
Open Exchange Management Shell and start by checking your Send Connector(s) :
Get-SendConnector
You should get the name of your send connector(s) – like “Default Send Connector”.
If you haven’t messed up with the port configuration of the connector yet, it should be using the default port -25. It is a good idea to confirm this with the command:
Get-SendConnector | fl port
Then change the port with the command:
Set-SendConnector –Identity “Your Send Connector Name” -Port 587
If you have only one Send Connector you can use that command too:
Get-SendConnector | Set-SendConnector -Port 587
Of course, it is a good idea to check the final result again with:
Get-SendConnector | fl port
Or even take a look at the full listing for the send connector:
Get-SendConnector | fl