This subject came up in a couple of different Exchange Server 2007 courses and is not really well publicized, so here we go.
First off, it is important to note that SCW, by default, has no clue about the existence of Exchange Server 2007 since it came out well before Exchange Server 2007 came out. If you try to configure your Exchange Server 2007 servers using the information for Exchange Server 2003 in SCW, you will definitely break your servers.
So, first step, copy the new Exchange Server 2007 information to the SCW location so it can be used. Copy exchange2007.xml and exchange2007edge.xml from the Exchange Server 2007 installation location ?:\program files\microsoft\exchange server\scripts to the scw xml file area at c:\windows\security\msscw\kbs.
The next step is to register the files by running:
scwcmd register /kbname:exchange2007.xml /kbfile:c:\windows\security\msscw\kbs\exchange2007.xml
scwcmd register /kbname:exchange2007edge.xml /kbfile:c:\windows\security\msscw\kbs\exchange2007edge.xml
The above commands will register the xml files with SCW and Exchange Server 2007 roles will now be available when running SCW.