Doesnt that setup come with a full suspension attached?
http://www.ebay.com/itm/LESU-TRACTOR...sAAOSwl8NVZjGV
It's weird that your axels dont have the pins on top for the wishbone, Also weird that, that entire suspension does not come pre assembled. Looks like there should be two holes on top and bottom where you can attached that center pin for the wishbone.
Maybe who ever you got this from didnt include it?