adding missing channels to digital tv signal

Does anyone know the reson that media center 7 does not allow you to add missing channels when using a digital signal. The only channels i seem to be missing that are important to me are espn hd, and just espn hd, regular espn, and espnu and espn2 hd work fine, my comcast broadcast two espn hd channels and neither are available, seems odd that almost every other channel is available and unlike with analog signal, media center doesn't allow you to add missing channels. there must be a reason for this

You can add channels to the Guide.

Open WMC and under Tasks, click on Settings.
When the Settings panel comes up, click TV > Guide > Add Missing Channels

i am using a hdmi input cable and that option is not available with my setup, i have been unable to find a reason for it just that it isnt an option and there is no walk around so when i want to watch espn have to whip out comcast remote and change channel with that

http://support.microsoft.com/kb/555370 this is what i have found so far but doesnt give me a reason and it doesnt make sense

Hadn't heard of that before even though it's been known for some time. Bummer. It could have something to do with licensing. I don't know. Looks like there's no work around for it either.

I am using a Hauppauge WinTV HVR 1250 PCIe Card, the WinTV software from Haupauge application shows all the HD channels, Windows Media Center only finds 1/4 of my available channels. It may be worth a look $9.95 Hauppauge: Support for WinTV v7