Modified trailing-stop

 

Don't know if this is the right place to post this, but I'll try:

I wanna have a trailing-stop-script in metatrader where I can define where my trailing will start, and at which price it will start to trail.

Example: I set my limit to 15 pips and my trailing to 5 pips in my modified trailing-stop-script. When the price reaches 15 pips, the stop loss will be set to 10 pips (5 pips behind 15 pips) and it will trail from there. So if the price suddenly goes up 20 pips (15 + 20 = 35 pips), then the stop loss will follow to 30 pips (5 pips behind 35 pips).

Can someone help me with this? Maybe it already exists, but I did not find anything.