I'm no block explorer expert or anything (BBMC, work your black magic and verify this)
But I just send a small transaction through mycelium wallet routed through tor, and I don't know if it uses an intermediate wallet or what, as I only looked for moments in astonishment, but I could not find MY sending address instead it showed a totally different funding source.
Maybe something to look into or a more BTC savvy person could educate me on why I am very very wrong?
You can't send coins from an address that isn't yours. That's fundementally how bitcoin works. Trace back the transaction one more step back and you'll find your address.