I have simular setup and I can record whatever is spooled through PC tuner. You do have to play recording on D* DVR. I have a very high end PC 3GHz AMD X2 3Gb Corsair RAM.
I would reccomend using an HD video tuner in your PC. Then connect using HDMI or HDMI-DVI. something like Asus Radeon HD 3870 (PCI-e 2.0, 512MB). Vista Premium media center has a DVR feature.