How to make an interactive minimap that supports in any Screen Resolution

I want to make a minimap with which i can interact. When I click at a position on the minimap, the Player moves to that position on the layout. When i double click at a position, the window scrolls to that position.

Currently I can interact with my minimap only when fullscreen in browser is turned off. When fullscreen in browser is set to Letterbox scale, it won't work. This is because for the interaction I used the action statement :

Player set position to (Touch.AbsoluteX-Minimap.X)*40, (Touch.AbsoluteY-Minimap.Y)*40

40 because Layout size is 40 times of Mininmap.

I had followed this tutorial: scirra.com/tutorials/271/veryvariable-mini-map-interaction

But I need to have Letter box scale fullscreen. I need to have the game supported in any screen resolution. So Please help...

how about use touch.x instead of touch.absoluteX. The later is typically not what you want to use. I've almost never wanted to use it.