That's what there may not be room for.  Ducati makes an expensive tool shaped like a C that curves around the edge of the head to grab the head nut.  The inexpensive tool is an extension that you attach to your torque wrench but needs a little room to work.  It can also be made from a wrench with a socket welded to it.

Here:
http://www.bevelheaven.com/stuff-for-sale-headnut-wrench.htm

And here:
http://motoreva.com/item.cfm?itemid=103&categoryid=171

Scott

Which reminds me...

Salty, get one of these puppies and see if your head nuts are torqued to spec.  If not, torque them up and see if that gets rid of your leak.

Scott