Italian bottom bracket Shimano BB-6400 fixed cup tightening - what tool? All,

I have a Shimano 600 Italian-threaded bottom bracket (BB-6400) and after riding with it for a few weeks, the fixed cup is loosening. I've since read up about Italian BBs and learned that the correct amount of torque needs to be applied to the fixed cup, somewhere in the 600 in-lb range.

My guess is that my HCW-4 isn't quite cutting it to get me to that level. I'd like to tighten it correctly and am looking for the right tool. If I'm in the market for a torque wrench, what tool or combination of tools will fit the 36 mm cup and allow me to reach the right torque?

Thanks.
This is the tool you want, combined with any torque wrench with the proper range. 



There are a number of applications where a torque is specified by the manufacturer, but no tool fitting for a torque wrench is available.

The BBI Torque Wrench Adapter allows you to attach any "normal" wrench to a torque guage, and get an accurate measurement of the torque applied to the fitting.

I've used it with pedal and cone wrenches primarily, but it would work well with the HCW-4 on a fixed cup application.

    

Barnett's Bicycle Institute Torque Wrench Adaptor