It isn't a transfer.
It's a cash deposit.
You can't "un-deposit" cash at a bank.
heh "un-deposit"... otherwise known as "withdraw".
I don't think you understand how this works.
You are making a cash deposit into MtGox's bank account.
Last time I checked,
most reputable banks will not let you "withdraw" money from somebody else's bank account. That's usually called a "bank robbery".
Maybe you know about some secret I don't?