Well you could if you're willing to hack around a bit, actually now that I think about it it might not be that difficult. I would load a blank sketch into the Uno, maybe
setup () {
pinMode(0, INPUT);
pinMode(1, INPUT);
}
loop () {}
just to be sure that the Rx and Tx pins are set as inputs.
This should get the Uno processor out of the way. Then run some wires as shown in that PDF and I think it would work.
Rob