Increase the greening up figure as percentage of balance figure grows?

[johnnycash]

Hi, can anyone tell me how to set up a green up figure in my Guardian program that correlates with the % of balance figure?
eg if my bank is £100 and I want to stake 10% on each trade (£10) I select 'percentage of balance' = 10% in the parameters tab. So I want to green up at 2% of that £10 (20p), but the 'green all profit conditions' only have a greater or less £ value? What I'm after is that 20p green up figure to move up or down with the percentage of balance stake.
I hope that makes sense and any answers would be great..