1. With your layout open Select Design New Footprint.
2. Set the grid spacing by pressing the g key on your keyboard to the radius of the circle the pins should fit into.
3. Change the rotation increment by selecting the User Preferences Icon on the tool bar. It will either look like this or depening on the Appearance you have selected. On the General tab set the rotation increment to the angle between pins on this part. Select Apply then OK to save your changes.
4. Place pins at (0,r), (r,0), (0,-r), and (-r,0) where r = radius of the circle.
5. Press esc to return to the Select an object tool. Drag a box around all of the pins to select them. Copy the selection and paste the pins off to the side.
6. Drag a box around the original set of pins to select them and press r on your keyboard to rotate the selection.
7. Go the pins that you pasted off to the side and move them into position. Then paste another copy of the 4 pin array off to the side.
8. Repeat steps 5 - 7 until you have completed your footprint.