Right. This isn't hard to understand - Congress was briefed on September 24, 2002 by Tenet regarding the uranium claim, which at that point was not yet proven a forgery. We're on the same page there.
The documents used to brief Congress, after which it voted to authorize Bush to use force, were still false. The question is, did the Bush administration know this when Congress was briefed?
I say, yes.
"CIA Director George J. Tenet told White House advisers in October not to include in the speech an allegation that Iraq offered to buy uranium from Niger, the Post said, citing unidentified administration officials. Tenet told them the information came from a single source, the newspaper reported."
http://quote.bloomberg.com/apps/news?pid=10000103&sid=aBK73LLyPKMw&refer=us
And of course the British is standing by their claims. To do otherwise is political suicide. If they do indeed have further proof, they need to reveal it. Until then, I don't buy it merely on their word.