Easy Mod_Rewrite Rule

I am having a terrible time with this. Figured I would let you nice people have a try at it. :)

All I want to do is redirect (invisibly):

any of these:
http://somedomain.com/sitedocs/
http://somedomain.com/sitedocs
http://somedomain.com/SiteDocs/
http://somedomain.com/SiteDocs

to -->

http://somedomain.com/SiteDocs.php

This is not working for me to do even the third one:
RewriteRule ^SiteDocs/(.+)$ /SiteDocs.php


Can someone give me a hand?