^^^ Interesting plan! Lure them out! hmmmm *strokes chin*
carsearch2011, I had a similar problem when I got my hatchback from the body shop many many years ago. Ended up using a bug bomb like this:

...which I got from the US but I can't seem to find locally AT ALL!
BUT in seeking a solution for my problem, I called Rentokill and it turns out that they can in fact scale down their fumigation process for houses (with the blanket etc.) and do a car. Can't remember the cost, but I remember hearing my wallet scream in the other room when he told me over the phone.
Give them a call and hear what they have to say.
If it can really be done, it'll definitely work, but as an alternative, seek out the help of maybe an agri shop or maybe William H. Scott for ant bait like
linkting suggested.
This looks like it might be effective.
