Hi Numb, Yes, it was me that posted that question on the Blender Forum! Thanks anyway!

You make it projected on that flat face in front of the bus. Then sample the projected image Alt + :paint) and it will not only pick the texture image but also its position and projected state. Now release the Alt key and paint it on the front of the bus. Also this is why it is very important to correctly align that free hanging face with the front of the bus.