JCo : funtion contains default value

Hi Experts,

I an getting some problem while setting values into JCO function after executing a this line...  destination.execute(function) .

Even if I am passing a ("")Blank String value to set into a date field in table parameter, JCo function contains a value like this "0000-00-00".

I dont when and how it's setting this value.

when I am passing a value in the format (yyyyMMdd ) it coverts to the format (yyyy-MM-dd)

It's fine when value is there, But I need a blank value from that field when I am passing a blank String ("").

Please help me.

Thanks

Gouri Shankar