if you have the park crank extractor (or similar) you shouldn't have any problems. just to make sure you are in the clear i would take the tool apart by unthreading the inside part from the outside. take the outer part of the tool that threads into the crank arm threads and snug it down a little bit once you have threaded it into the crank. now that the outer part of the tool is secured in the crank go ahead and thread the inner part in just as you would with a normal BB. the operation should be the same.
What you have is a square taper bb but its a different style. back when the 600 cranks were out it was pretty common to find bikes with this type of bb. these days you typically see 8 mm allen bolts thread into the bb axle rather than what you have on your bike.

for reference:
http://parktool.com/repair/readhowto.asp?id=103