just wanted to say that i have the credit card response on my "order failed" page as well. Its not as clear/enlightening as you may want it.
Unfortunately the response comes from the credit card the user is trying to use. And many times it gives a general response - card declined. Only sometime do you get a clear answer like "avs mismatch" or incorrect address etc.
theres not much you can do since its not your code, not your gateway etc. Its simply the credit card company the user is using. Its all dependent on them as to how clear the error message is.