Boots will not ship until Spring 2012, which officially starts March 20th. If you try to place an order the Revzilla system will give you the option of being emailed when they are actually in stock.
The Dainese conversion chart says US size 11 = their size 44, but an authoritative generic conversion chart says Euro size 44 = US size 10.5, Euro size 45 = US size 11.5, you can find the chart here:
It might be best to simply measure your feet in centimeters, back of heel to tip of longest toe (best done with heels against a wall, standing up, with someone else reading the ruler). One Euro shoe size equals 2/3 cm, so size 44 = 29.33 cm (11.55 inches), size 45 = 30 cm (11.81 inches).
Remember - it is always easier to wear thicker socks than to cut off the ends of your toes.
1 year, 3 months ago