Timestamp with dates older than 1970

Hi everybody,

I want to create an online War Diary, from my grandfather’s paper diary he kept during World War II.

The problem is, I found out I cannot put a really old date for timestamp for my WP topics. For example, I write a post and want to put a date 19 September 1941, but when I do this, wordpress automatically changes this date to something totally diferrent, eg: 1973.

Is this a known bug? Is there a way to do this in WordPress? If not by default, then by a plugin or hack?

Thankyou very much.