I'm afraid I cannot answer your question re Creda timer as I have exactly the same problem and have been struggling to find the answer from other people but no-one so far can help. As you say it is so frustrating - I'm sure it is just a simple thing like how to adjust the Manual setting with the Auto and clock. I am writing to see if by any chance you have solved the problem meanwhile - and hopefully could let me know.
Best wishes
Magpie
October 2010