Ok, I've been bouncing around the net trying to find out a way do do something with format but either it can't be done, unlikely, or I've missed something simple, probable

I have a double that I need to format to a string and have it padded with zeros. My field needs to be '0000000.00' so if the number is 1.2 then the string should be '0000001.30' or if the number is zero the string should be '0000000.00'. Should be simple, I thought, but nothing is making any sense here at the end of the day.

Bill