You need the special tool to clamp around and turn the six sided nut. But if the rear joint is broken, there isn't much to hold on to to get the back half of the shaft off the diff input.
Try pulling what remains of the driveshaft off the diff and see what is still attached.
E92 335i/6MT Dinan Stage 3: intercooler, oil cooler, intake, flash, exhaust, LW dual-mass flywheel.
Vishnu PWM methanol custom trunk mount, Diffsonline 3-clutch Salisbury custom diff, Ohlins Road and Track coilovers, Vorshlag camber plates, much more...
E28 M5 w/ buncha stuff, R171 SLK350