Maybe it's only on the North American version, but if you can find that rubber plug, you wouldn't need to drill through any metal. It is a solid rubber plug, located between the passenger footwell area and the wheel well on the outside. You can only see it by sticking your head in the passenger foot area - like I said it comes out in the wheel well, so you won't be able to see it from the outside unless you take the plastic wheel liner out.
Mitz probably has the easier method, I just wanted to give another possible option.
View my fuel log 2015 Mirage DE 1.2 manual: 43.4 mpg (US) ... 18.4 km/L ... 5.4 L/100 km ... 52.1 mpg (Imp)