1) open Terminal.app,
2) go to the folder where is your script file
3) and do this :
plutil -convert xml1 "my_ammscript.amsf" -o - | sed s/vega.stga.dom/aldebaran.stga.dom/g | plutil -convert binary1 -o "my_ammscript.amsf" -
To see the result :
open -a "Property List Editor" my_ammscript.amsf
with 10.4.11 use
plutil -convert xml1 "my_ammscript.amsf"
sed -i .old s/vega.stga.dom/aldebaran.stga.dom/g "my_ammscript.amsf"
plutil -convert binary1 "my_ammscript.amsf"