In reply to tallsteve:
Interesting. And sorry to hear of your pains.
Both my partner and I have been using these boots the last 10 months or so because they are the only boots that DON'T hurt our achilles. My partner had severe problems from years of hill work and running, and last year needed specialist surgery to scrape out the tendon/bone muck. I've always had problem bony heels and am heading the same way.
The Monoliths are the only boot we've found (beside other Mammuts -- Cliffs, Envies -- of which we also now use) that have ample heel space so there is no contact at the achilles insertion point. That big heel bulge these boots have. Rare for a boot, with all these modern aims of heel clamping etc.
Don't quite follow where you are getting pressure, but are you sure you're not getting biomechanical stress/trigger-point type pains in your calf, due to postural problems? Where exactly is your pain? And do you also have very tender trigger points up in the top rear of your calf close to the back of the knee (feel around kneed the muscle)?
If not then might be this boot shape just isn't for you. EG, Salomon Guides kill my heels after 10 mins.