I decided to help you only because you used “cordially”. 
First, get the vector from the character to the target location. Then, get the forward vector of the character and add the rotation of this forward vector from the coordinate system base. You have to find out what it is. By doing so the vector will be shifted to be relative to the direction the character is facing. YOu can use the camera forward vector as well.
After you have the rotated target vector, extract ONLY the X and Y components of the vector and use those as the 2D vector of the widget arrow. This will cause the system to point in the correct direction. You might have to rotate the arrow 90*n degrees depending on the rest of your system, so try it once and see if it point towards the target or stays at a fixed angle to the true direction.
HTH