I don't see where I said proof, and I believe proof to be a personal judgment rather than a certain thing for everyone. What constitutes as proof to me of something, does not necessarily constitute as proof for anyone else.
"So using Rumsfeld's old "cover-his-ass" speech as your proof is a bit vapid."
That is the speech from 9/10/2001, the day before 9/11, that I linked to. If you read the whole speech it's pretty obvious he's laying out the case for his DoD budget and I would think saying we've "lost" 2.3 trillion dollars wouldn't help that case much.
Dov Zakheim is only commenting because he was in the Comptroller position at that time, he is not responsible for not knowing where the 2.3 trillion is because that is total untracked expenses before he was in the DoD, the $2.3 trillion was found in a 1999 audit, 2 years before Zakheim worked for the Bush DoD. That article also states that "these "unsupported" transactions do not mean the department ultimately cannot account for them, she advised, but that tracking down needed documents would take a long time".
There's more on it here if you want to see more detailed explanation of what I am saying. But like I said, make up your own mind. I'm just sharing information and you asked if I had anymore documentation.