OSX Authentication box

[Richard Miller]

I need to respond to an OSX Authentication dialog box from inside Rev  
using Applescript. I tried using the following:

keystroke xxx  (where xxx = the users password)
keystroke return   (to trigger the OK button)

This works fine on my older MacBook using 10.4.11, but for whatever  
reason, it doesn't work on a newer desktop Mac (also using 10.4.11).  
It just ignores the Applescript "return" command and leaves the  
Authentication dialog box open. ("Enable Access for Assistive  
Devices" is turned on.)

Is there some other way I can have Rev close that dialog box after  
it's used Applescript to insert the password?

Thanks.
Richard Miller