"Authored on" field rejected

Hi,

I try to import a large set of nodes. I set the "Authored on" field to a certain column in my csv.
The fields are formated like this:
4/8/08 - 12:00
The time is always - 12:00

The custom date format I am trying to use is:
n/j/y - H:i

But when I try to import it, I get a "You have to specify a valid date." exception. I can't find my mistake. Am I doing it wrong or is it a bug?
But it