It would not be recomended so often and in the sticky if it was not easy or if it was risky.
You can also get these little adapters which to the crossover for you, about £2 they cost. OcUK may have some under cables ---> Other.
They are a bit expensive considering, but they are 100% risk free, not 99%
And read the Sticky next time
/Bloomin new people spamming
EDIT:
http://www.overclockers.co.uk/acatalog/Online_Catalogue_Other_Cables_153.html
They only seem to have a 3pin 12v to 10v adapter. A competitor stocks them I am sure; although I see why OcUK don't as they are a bit pointless when it is so easy!