Export to XML file

Hello,

I am using Access 2007

I have a table that I want to export it to XML file. I am able to do this by
using export data xml.....

The problem that I have is that in my table, one of the fields can have null
value. When I open the exported XML file, I expect to see field1/field1
if the field1 is null value for that record. But I don't see this at all.
How can I force Access to export null value to xml as well?

thanks a lot,
Boon