First, props to this hint, which inspired and provided critical data for this hint. I have found that most, if not all, of the Olympus C-Series (and possibly other series) cameras' RAW formats can be supported by the dict entry for the C8080WZ.
The file that needs to be edited is in /System -> Library -> Frameworks -> ApplicationServices.framework -> Versions -> A -> Frameworks -> ImageIO.framework -> Versions -> A -> Resources -> Raw.plist. Use your favorite text editor to find a line containing C8080. Next, copy everything from that line to the line containing the term </dict>.
Once you have made a fresh copy of the dictionary entry, simply change the name to match your camera's identification string. For the 5050, this is OLYMPUS-C5050Z. If you don't know your camera's string, import an unsupported RAW image into Aperture and look at the camera designation in the metadata, or, do a strings command on one of your .ORF files.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20061027015638765