If you would like this banner in the game, you can download this file: http://ultimate-gamer.org/banners_b.dds
Replace this with the file in your game's texture folder, this only replaces one banner.
Take a backup if you want to keep the old one.
To use it in game, select it from the banner menu when prompted.

OR:

If you want to replace your banner in a savegame where you already have chosen a banner, you can download this image:

Then replace this manually with the banner you are using. They are found in banners_a.dds, banners_b.dds etc.
(It is easy to understand once you see it)

This can be done in various programs, i.e photoshop (needs this plugin: http://developer.nvidia.com/object/photoshop_dds_plugins.html#downloads)

It will automatically be added to shields and surcoats as well.

You can also use this technique to place your own banners if wanted.