Help Trip Computer

[fuzzy1]

Hi all, need some help, got me a 56 reg fiesta 1.4tdci zetec the other day, couple of problems, the milage trip zero`s out every time I switch the ingnition of most annoying as I like to set it everytime I fill up then I can work out the mpg`s over the month, sad I know but there you go, getting tight in my old age, also the clock on the radio (cd6000) also does the same and starts from 00.00 every time I start up, hoping some of you long time owners can give me some info.

Thanks in advance