Install sfz, load it in cubase (it's a vst instrument), and load the natural studio sound font in sfz. Then you will need to either create a midi track or use a midi controller (keyboard) to trigger the drum sounds.
That's about the best free solution that I know of.
sounds like the all mighty mother of cheese, imo. if the samples were'nt washed in verb and compression, then maybe they could be doctored up a bit to sound ok.
also, with sfz, you can find alot of different soundfont kits for free. the natural studio kit sounds pretty good though.
The Natural Studio Kit sounds damn good for being free. If you get creative and maybe use a soundfont editor and use multiple instances of SFZ, you could have alot of control over the Natural Studio Kit samples. Or, if you can find a free sampler to use with the wav files instead of the soundfont samples, you'd be better off.