Word 2003 - Empty search string

[Steve B. [Labo.Net]]

Hi

I build by own research service to be called within Word 2003.. It works fine, but I'd like to allow the user to enter an empty
string (which is not allowed as Word does not query the service if the field is empty).

Is it possible to change this behavior ?

If not, is it possible to put using object model, a custom string in this field ?

Thanks
Steve