1.8 duratec big end bearings

Hi guys.  I've got a 2004 mondeo with the 1.8 duratec engine.  There's a slight knocking from the big ends and I'm thinking about changing the bearings but a couple of things are bothering me.  According to the haynes manual, Ford say that due to the tolerances of the crank assembly, no work is possible on the bottom end of the petrol engine and the whole thing must be replaced as a unit yet its possible to change them on a diesel engine?.  The big end bearings can be replaced on just about every other make of car and the bearings are readily available from motor factors so surely they can be replaced.  Also, ford don't list any torque settings for the big end bearing caps (presumably for the above reason).   Basically, I have two questions.  Has anybody else successfully replaced the big end bearings in a duratec engine and does anyone know what the correct torque settings are for the end caps?