Find path to closest point on a building


I am trying to use the pathfinder to run towards a building in a RTS game and start attacking it at close range.
I am using Seeker.StartPath() with position of the building as argument.
Since this position is not accesible, the pathfinder finds the closest point on recast graph to this position as expected.

However, this position is always the same, and results in situations where the unit runs around the building first. Is it somehow possible to force the pathfinder to find the closest position to the building relative to current position of the unit?