Removal of Tiagra Hollowtech BB

Ripley Posts: 16
edited August 2009 in MTB beginners
Hi, I'm replacing my tiagra bb with an mtb XT Triple chainset.
Everything went fine until I got to the removal of the drivtrain side bb cup. I have that weird looking shimano tool that fits the cup. It's really hard to get a turn. I've been bashing it with the rubber hammer but its started to shred the grooves in the cup - I decided I need help!

The cup has an arrow that says 'tighten' and I'm going in the opposite direction to loosen.

Any ideas? My fear is that I could ruin the threads in the frame?

Many thanks,