A tool? I highly doubt it. You might be able to jury-rig something to give you more leverage. Some of the elastics have hooks on the end and some have loops. The ones with hooks are easier to install, but it's usually just a case of having small, but very strong, fingers. I sometimes have to use needle nosed pliers or small vice grips just to get a good grip on the danged things.
Seeing as I just need to get it to the shop on the weekend to do a trade in I might let them deal with it. It's in there pretty good as is, and should last an hours drive.
if its like my Vulcan, stretch the elastic out and kinda fish it around. Get as much slack as possible, and hold it tight to the top of the battery, with the slack hanging down. might take a few times.