Excel 2007 : bracket on negative numbers in workbooks

i seem to be missing the conditional formating for negitive numbers in brackets. when i go to add it in manually it remembers it for the current workbook but doesnt seem to remember if i create a new document. how do i get it to save the custom format so i can use it in other documents.

the code i am trying to add is

#,##0;(#,##0);0

Create a workbook template (.xltx) that has the NORMAL style defined to suit your preferences. All new workbooks will include that new style.

Does that help?