[Sacred]

I'm wanting a reference from my current employer, I've asked both the senior manager and the managing director but both have said if I write it they will sign it. Can they really ask me to do this? I need a reference for my uni application and since I'm not longer at school it has to be from my current employer.
Its really hard to write a reference for myself, even worse is the fact they would be able to read a page about me blowing my own trumpet and show it to anyone else in the office they want to. I think they wont write me a reference because if they do and I leave for uni they will be quite stuck (their not very good with computers and I do a lot of computer work for them, ranging from finance, advertising, general documents, sales etc).
Is their anything I can do? I will I have to try and sit and write a reference myself which is hard to do for someone else let alone myself.