You can make it work in Windows 7 with help of Windows XP Mode, here is all the details: Windows7-kb3 ADUC with exchange 2003 and Live Communications Server 2005 extension - JBKB
RSAT is good but if you administer Exchange 2003 or Live Communication Server 2005 I prefer this solution: Windows7-kb3 ADUC with exchange 2003 and Live Communications Server 2005 extension - JBKB