To thread starter,
Previous threads give a good insight to what is involved and it's one of the best jobs going. Enjoy.
As for signing the loadsheet.....don't do it!!!!!!!
The loadsheet is signed by person producing it and the capt/fo. Someone who is not fully w&b trained SHOULD NOT SIGN THE LOADSHEET.
I haven't got the JAA/CAA requirements for loadsheet responsibilities to hand, but if there are any questions on the above I am very happy to answer them in due course.