As a stop gap, could you soft a kick 3.1 rom legitimately obtained from Amiga forever? I think you would need to rip the rom from WinUAE to get it to work in your A3000.
You could use a version check in the startup sequence to see if 3.1 was kicked, and if not get it to kick it, then on the reboot it would boot up workbench 3.1 upwards.