Problem with trigger Martingale in horses

Hello,
I'm having a problem creating a trigger again LOL, I created a trigger to Martingale in back, IF (losses = 0, default_backa, hist_1_backa * 2), but I wanted him to not bet the value clearcut back, but an amount multiplied by odd to me that the value clearcut in back, and in case of miss, I make the account and put the value lost over the amount you want to win.

Hi
Is this one any good to you?
http://marketfeeder.co.uk/solutions/staking-plans/simple-staking-plan-back/

It was so "simple" that I did not see even that was LOL, thanks