need a stop lose trigger for in-running???

[bentos]

could someone please tell me how i can setup a stop loss for in-running i wud love to have a button where when i press it if i get the price reaction correct i make a green book of x amount but if the price goes the wrong way it triggers a stop loss to lose x amount
eg. i want to bet £10....if the price goes correctly i green up to profit £5 on every horse if it goes the wrong way i lose £2.....the stop lose wud have to be cancelled once the race greened up just in case there was a faller at the last when clear.....would this be possible if so could you explain what i would need to do? much much appreciated if you could

regards