We need to increase the maximum message size in our SBS 2008 system. Right now we're at the default 10200 KB level. We'd like to increase that to 42000 KB. Currently we use the POP3 connector to receive incoming mail, and send out via our ISP, Comcast.
I've changed the Exchange Management Console > Organization Configuration > Hub Transport > Global Settings > Transport Settings > Properties > Transport Limits changing Maximum Receive and Send size to 42000 KB.
I also changed the Exchange Management Console > Server Configuration > Hub Transport > Default Server Properties > Maximum Message Size to 42000 KB. and SBS Internet Receive Properties to the same setting.
We're still not downloading 15 MB messages from our POP3 accounts while we're getting everything else.