Set the date and time in menubar to be in a specific format I want the menubar to display the date and time in the menubar as follows: 

2012-10-03 09.12.14


which translates into Year-Month-Day 24hr.min.second

What I've tried: 

Gone into System Preferences > Date &amp; Time > Clock

Selected: Digital; Display time with seconds; use 24-hour clock 

This gets me close to having the time right.

Gone into System Preferences > Date &amp; Time > Date &amp; Time > Open Language &amp; Text > Formats > Dates > Customize

Changed every date format (short, medium, long, full) to have yyyy-MM-dd

Gone into System Preferences > Date &amp; Time > Date &amp; Time > Open Language &amp; Text > Formats > Times > Customize

Change every time format to kk.mm.ss

The problem: 

It still shows the date like: 

3 Oct 13:19:12


in the menubar. 

Details:

I am running Mac OS X 10.7.5

Any help or suggestions you can give, much appreciated!
There is a free app called Day-O that is flexible and can do what is being asked:  https://shauninman.com/archive/2016/10/20/day_o_2_mac_menu_bar_clock