If the toolbox is aluminum, which is almsot always will be, then you would have to use an antenna that doesn't need to be grounded. If you don't like drilling holes you can also use a magnetic mount or maybe one that gets it to come out from the hood, at least the holes would be hidden.

http://www.firestik.com/FAQ.htm
http://www.firestik.com/Tech_Docs.htm

This site is a maker of antennas, and can answer lots of questions about grounds, antennas, ect.