Import signatures list

Hi,

I need to import a signatures list, which was collected with Google docs.
I export the plugin signatures list via mySQL to CSV file, add the old email lists according to the plugin fields, everything seems to be ok. but when I import the file back. all the fields look good, except the date which looks like that:
Nov 30, -0001
What am I missing? should I set the column in a specific format?

Thanks a lot!
Raphael