To Lay
Place a $6 @ 1.01 lay
Amend this lay by the amount you want to stake. You'll end up with two lays.
Delete the $6 lay
Amend the price of the remaining layto what you want

To Back
Same but put the $6 on at 1000

Some of the trading apps like Fairbot and BetTrader Pro do this for you automatically. Get one of these - you can't work properly from the Betfair UI.

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Pixie

"It's worth remembering that profit isn't profit until it's spent off the racecourse." -- Crash