The trick to using liquor instead of cocoa powder is to understand that liquor by weight is +/- 50% fat. You can't use liquor and not adjust the other fats that the recipe calls for (butter, vegetable oil, etc).
For example if your recipe calls for 1/4 c of cocoa powder, you need to use 1/2 c of liquor and reduce the other fat in your recipe by 1/4 c. it's really that simple.
I think you'll also find that by reducing other fats, your baked goods will be much lighter and fluffier than using shortenings, or oil. At least that's been my experience.
Cheers
Brad.