Date Format in Format Cells

Could you please help me how to create in format cells a date format using only upper case letters, example: August 05, 2012 for AUGUST 05, 2012.

if August 05, 2012 is text

if August 05, 2012 is text and in cell A1, use =UPPER(A1) then copy and paste over values.
if the cell is a date, use:
=UPPER(TEXT(A1,"mmmm dd,yyyy"))

Date Format in Upper Case Letters

Thank you. What I need to know is how to create the format within Custom Format in Format Cells, so whenever I write a date it'll come out automatically in the same cell.

it's not possible.. the way

it's not possible.. the way above is the only way