Non-Valve Steam Game Install from CD

[Naph]

I installed Dark Messiah again, via CD and onto my drive. Then I tried playing, didn't work. So I decided to import to steam in desperation.

But I come home from work to find out it god damn downloaded it. 84%...
How do I install a game from the cd, into steam?

It's not a 3.7gb update either ...

[PimpinPenguin]

When you install Dark Messiah you can copy it's GCFs into the Steam directory.

[Naph]

*Slap's Forehead*
Didn't think it had them, but closer inspection; they're there.