How do I set a NULL value for the parameter field

Hi

I've another question. I'm going to set single values for parameter fields.

// e.g. set today for StartDate parameter field
fc.setCurrentValue("", "StartDate", new Date());

It should be possible to set a NULL value for date parameter fields.

fc.setCurrentValue("", "StartDate", (Date)null);

But this do not work. How do I set a NULL value correctly?

Thank you in advance.

Best regards,

Thomas