Short days and Short months don't work

I've used both advanced fields to translate in italian language but they don't work. In frontend I got and "undefined" text for the month and an horizontal scroll bar instead of the days list.

This is what I've used in the respective fields:

for months: ["Gen", "Feb", "Mar", "Apr", "Mag", "Giu", "Lug", "Ago", "Set", "Ott", "Nov", "Dic"]

for days: ["Lu", "Ma", "Me", "Gi", "Ve", "Sa", "Do"]

What's wrong?
Thanks in advance.

Hi deltafidesign,

It works OK when I test see here - I copied and pasted your lists into the Datepicker boxes.

Please post a link to the form so I can take a quick look.

Bob