unmounting volumes

: I am trying to write a script that will perform the
: following tasks: 1. When file(s) are dropped on
: the script icon a volume from another computer on the
: network is mounted on the desktop; 2. The file(s)
: are copied to that volume. 3. The volume is
: unmounted, i.e is dragged to the trash I have
: succesfully written a script that completes the first
: two tasks, but can’t seem to get the third task
: completed. Any help is appreciated.
try
tell application “Finder”
activate
select folder “XYZ”
put away selection
end tell on error end try