Change permissions on a .dmg file

This is my first post so hi!

I have an os x server that we are multicasting image replication using Netrestore and Carbon Copy Cloner. I’m writing a script to automate the process a little.

The process goes like this: Carbon Copy Cloner images a machine via firewire and saves the image to the iDrive (second drive). The resulting file is named whatever the target machines hard drive was and asr.dmg ie: Macintosh HD_asr.dmg. The resulting file always has read only properties.

My script gathers the new name for an image and attempts to rename the file. The script will do a lot more than that but I’m stuck at the renaming. I’ve spent four days trying to figure out how to change the files permissions.

Here is my code:

on retreiveimage() -- script to load image name and place values into new property
	set thePath to (path to preferences as string) & "prw_prefs.scpt" -- set's thePath for saving image name etc
	script prw_loadprefs
		property prw_newimagename : ""
	end script
		set prw_loadprefs to load script file thePath
		tell application "Finder"
			set new to choose file with prompt "Select your new image: Should be Macintosh HD_asr.dmg"
			set the name of file new to prw_newimagename of prw_loadprefs
		end tell
	on error
	end try
end retreiveimage

I just included the code for the the area I believe should do the permission change.

sorry don’t know the exact code but here’s where to look:

you can call any unix command from applescript-

Tell application "System Events"
do shell script "whatever"
end tell