COPY FROM and multiple null strings

Hi,

I've run into a little snag in my data loads, and I come seeking
advice before I resort to an ugly workaround...

I have a function which runs COPY FROM several times. My problem is
that my data provider uses symbols to represent nulls - there is a
different symbol for each different data type. For instance a null
date would be '1900-01-01' and a null string would be '#'.  Is there
any way to define multiple null strings in the COPY FROM command?

As always, any suggestions would be much appreciated.

Thanks,
Mark