COPY from and NULL values for double precisions fields

Hi Guys,

I'm currently mucking around w/ importing TAB-delimited files;
how can I import empty values into a double precision field?

COPY complains about nothing between the TABS, about "\N"
and other variations, as being
"invalid input syntax for type double precision:"

What *is* valid syntax for this?  Can't find it for the life of me.


Cheers,
Andrej