Excel 2010 changes date format

I am having trouble with Excel 2010 not displaying correctly the date formats. For example, I have the following date format in my database table (dd-mmm-yyyy) and in the related pivot table I get the following date format (mmm-yy). I tried removing the field from the pivot table and then including the field again, but this did not correct the problem. Since I need to choose date specific records in my pivot table, this problem makes it difficult to know which date is being referred to.

Does anyone have any suggestions? Thanks.

I appreciate your reply, but this is not a value field, but a filter field. I can't change a number format on a filter field. Excel 2010 does not give me that option.

Specifically, this is a column label field within my pivot table.

I opened your sample worksheet and saw that you are able to change number formats in your row labels. However, for some reason I do not have that option in my worksheet. The "Number Format" button does not appear when I try to change the Field Settings in my Row and Column label fields. Do you know if there is any other way I may access the button?

I am including a print screen.

I tried recreating your same sample database and pivot table and I do get the option to format the row label. Apparently there is something corrupted in my table. Thank you.

How do I handle the fact that until the event occurs, the field will be blank?