Change date format

Hi.
I usage Openpli 4 on my Vu+ Duo 2 using orginal skin.

How can I have change the date format ?

Currently the date are shown as 06.05.2014 or in some case as 6.5. (dd.mm.yyyy) or (d.m)

This are not standard date formate in Sweden. I like it to show the date formatted as yyyy-mm-dd e.g 2014-05-06

All help are very welcome