making a file readonly

Hi,

I’ve recently built an installer with realbasic, and have been using applescript to do things that RB can’t seem to do. (make an alias, get disk volume information, etc…)

The (hopefully) final thing I need to happen is to be able to make some files read-only after the install.

I can’t seem to find an example of setting file permissions that I can get to work. I have seen the file writable function, but I can’t get that to work.

Can anyone point me in a direction, or show a sample of how to make a file read-only (which is different than locked correct? sorry, I’m not a native mac user).

I will need this to work with OS9 also, but first things first…

Thanks for any responses…
Jason