First of all, unless the Ka is well greased (unlikely) then you'll probably break a few bolts along the way (I did).
0. Drain the oil.
1. First remove the heat shield from the engine.
2. Undo the catalytic converter and drop it downwards.
3. Remove the dust cover from the gearbox.
4. Remove all bolts from the sump. Need one hex bit.
5. Drop the sump off.
6. Fit gasket to new sump and reverse the above process.
I can't put photo's here (why not?), so I've put them on Picassa. Can't guarantee they'll stay there for ever. See: http://picasaweb.google.com/Capturama/FordKaSump
Dave, August 2008