Zippo butane lighter

How do you fill a Zippo Multi Purpose Butane Lighter?

Google:

http://www.pipeshop.com/faq.htm#refill

you can't...there is no way to tell if the butane is really going in, unless you have a lighter that has a viewable fill tank...this is the most frustrating thing with butane lighters...it seems they work when you first get them, but then you go to refill it and it may work for 1 or 2 lights, but then not again...it sucks...the best thing I ever found was the large disposable lighter labeled 'CUBAN' but you can't find them anymore...you can't order good disposables over the internet I guess do to safety concerns...the situation just sucks