OpenOffice Date and Time Custom Formats

During 1st semester in Systems of the Earth, I just did a handwritten table of contents, but I ran out of room and was unable to continue adding stuff after 11/15/2011.
For 2nd semester, I will be using OpenOffice for its tables. At the end of the week, I'll just add whatever notebook work we did to the table.

The only problem is the date format. I want my date to be formatted as M/D/YYYY.
For example, 2/4/2012 (M/D/YYYY) instead of 02/04/12 (MM/DD/YY).

However, whenever I tab over or hit enter, it changes automatically to the format I don't want, which I just showed above (02/04/12).
I've tried customizing the format before, but it didn't work, and now I don't even remember how to get there.

Also, if I choose to start using time on it for some reason, I would like it to be this format: 9:19 AM, 11:22 PM, etc.

Here is a screenshot of the format I don't want:

Spoiler