Are you talking about using the probing? What year is the machine? Is it the Renishaw probing? And you have the TS27 presetter for tool lengths?
If so, check these threads and see if it helps any. We've discussed this stuff to death but if you have any questions, fire away:
http://cnczone.com/forums/showthread.php?t=52127 http://cnczone.com/forums/showthread.php?t=52502 http://cnczone.com/forums/showthread.php?t=50221 http://cnczone.com/forums/showthread.php?t=46742
And especially this one:
http://cnczone.com/forums/showpost.p...3&postcount=24