Question : Raid 1 Hard drive failed PowerEdge 1850

I have two hard drives 36GB each and they are Raid 1 configuration.  

It is PERC 4e/Si Raid Controller.  Can I swap the failed hd with another one?  What i need to make sure before I purchase and before installation, any instructions on how to install?

Answer : Raid 1 Hard drive failed PowerEdge 1850

Exchange 2010 seems to support this feature using Transport Rules.  Just a couple of quick "Hey, look at this cool new feature!" links I stumbled across:
http://www.networkworld.com/community/blog/standardized-signatures-exchange-server-2010-?source=nww_rss
http://csolarz.spaces.live.com/blog/cns!DBA51C9F747ECD38!531.entry?wa=wsignin1.0&sa=10332669
http://markswinkels.nl/2010/01/18/how-to-exchange-2010-e-mail-signature-based-on-active-directory-information/