How can I mirror props? and water issue

I made a map thats mirrored instead of rotated.

I have half the map done with props and need to copy/mirror+rotate it now.



Also have a problem with the deep water when zooming in and out, and it looks ulgyer when zoomed out then in the editor.



http://www.bluestrike.be/tempspul/supcommap.jpg|||I wonder about how to mirror props and decals too. I made a map like that. I ended up copying props/decals and manually placing them on the other side.