My headphone's volume control won't work with my iphone?

I have an IPhone 3GS, and I have Samsung headphones (earbuds), the ones that block out noise (I think, I got them for my birthday). And I'm pressing the buttons on the little remote that's attached to the wire and there's the three buttons, a play/pause button, and an up and down volume buttons (one of each, obviously). I kept pressing them, and my loud music (A Rammstein song if you really care.) played through when I hit the play/pause button. Why does the play/pause button work, but the volume buttons don't? It doesn't make any sense. I mean, why design them like that? More importantly, is there a way I can get the volume buttons to work?

You need a headset designed specifically designed for an iPhone.