Setting new default application for Appleworks (cwk) files

I just bought the iWork family pack. We (my wife especially) have many old Appleworks word-processing files for which we would like Pages to be the default application. I attempted to use the normal technique (right-click file, select other application, check box for all files, and choose Pages) to make Pages the default application. It *seems* to work and the particular file opens with Pages. I've used this technique before and it always worked (to open .jpg files with Photoshop, for example).

However, the next time she clicks on a different .cwk file, it still opens with Appleworks. So I moved the Appleworks application folder to an "uninstalled.applications" folder in the user directory. Then when she clicks on a .cwk file, it tries to open in Keynote!

Since she has no immediate need for Keynote, I move it as well to the uninstalled.applications folder. Now it tries to open the .cwk file with Numbers! I do not wish to uninstall numbers.

Am I doing something wrong? Is this a Snow Leopard bug? The same thing happens on both our iMacs. I have not yet tried it on our laptops. All of our systems are on the very latest Snow Leopard releases (10.6.2) and I have just run software update ("Your software is up to date.")

Thanks in advance for your help. Please let me know if this question should be posed in a different forum.

Roger