No. The signals in the DVI plug are not normally the same as in a component HDTV signal, thus the video card needs to know how to output them like that. So, unless your card has the outputs to do it, you're petty much screwed.
Probably the little switches on the top of the thing are like jumpers on an old mother board, and by closing certain pins on the DVI port, it tells the video card to output in component HDTV, but that's my guess.
Now, if your HDTV has a HDMI input, then you’re in business, because any card with a DVI output, enough power (say any thing from a Geforce 4 up, but just for high res), and decent drivers it can run your HDTV. I'm using a PCI 5700LE on my MCE shuttle here at home to do just that actually. All you need to do is get a cheep little DVI to HDMI cable and it will run you HDTV through that no problem.