When configuring actions on detected spam on Exchange 2007 and 2010, there is no option to send it to the junk email folder when configuring it on the EMC. This is absurd. It looks like this (shown here are the actions on the content filter):
As stupid as it is, the way you can configure an SCL to be sent to the junk e-mail folder is through the PowerShell.
This command will send all junk with an SCL of 4 or higher to junk e-mail:
Set-OrganizationConfig -SCLJunkThreshold 4
I put this command on all my Exchange servers. I also disable all outright rejection of spam. Users hate it when legitimate email gets rejected. All spam goes into the junk email folder.
More info on this issue is located here: