What you are describing sounds similar to tick offset combined with stop loss.
1) In the tick offset settings tab set the tick offset to 100 and tick "Ticks = %"
2) In the stop loss tab select odds instead of offset ticks and enter 2 in the odds box. Tick enabled.
3) Place your lay bet.
4) Turn off tick offset and stop loss by clicking on the green ticks at the top of the screen. They will change to a red cross to indicate they are no longer active. This is to prevent further bets that you place having these settings applied.
5) Do not change markets. If you do it will not be able to monitor the bets.
As soon as the lay bet is matched it will place a back bet at double the odds. If the lay odds come down to 2 or lower then the back bet will be cancelled and a stop loss back bet will be placed at the lay odds minus 1 tick.
There is a bug in version 1.1.0.62 which affects this type of stop loss bet so I urge you to install the latest Beta version before trying this.
See
http://www.gruss-software.co.uk/forum/v ... php?t=3922 for download link.
You can also read about these features in the user guide here
http://www.gruss-software.co.uk/Betting ... p/help.htm