This should not be to difficult, I done something similar with my map except that it is not on the borders, but that is not too hard too add. I created icons for the landmarks and positioned them as on the minimap through pan.x and pan.y IIRC. The player is shown as a white arrow icon that rotates when the player rotates too. I made the whole minimap through icons and used a small terrain like image as background. It is kind of late here and I am not behind my laptop, tommorrow I can give you a more detailed and usefull description.