I just did this the other day using a 1/2" drive socket over the nut with an allen key through the middle of the socket. Used large mole grips to turn the socket. Guess i was lucky they werent too tight.
Not sure how i will torque them back up, i think GSF sell the special too for this
98743 STRUT NUT TOOL 2PC GENERAL USE*** 7.25
98744 STRUT NUT TOOL 3PC GENERAL USE*** 8.90
dont know which one though, anyone?