Clamp one end of the spring in a vice. Bend spring and insert washer in the gap between adjacent coils. Bend spring the other way and insert another washer 180 degrees offset from the first. Repeat until the spring is long enough to slip over the two location lugs. Fit spring. Remove washers.
I have done it by fixing a length of wire into the front end of the spring, fitting the rear loop onto the c/stand mount, then using a long screwdriver as a lever through the wire loop stretch the spring until the front loop will locate over the frame mount. Last time I tried it I couldn't get it to work for some reason so reverted to the washers method.