UpdateFields element does not work for Office 2003

Question

I am using the updatefields element as stated here:

http://msdn.microsoft.com/en-us/library/documentformat.openxml.wordprocessing.updatefieldsonopen.aspx

When I open the document in word 2007/2010 I get prompted to update the fields, but this doesn't happen on Word 2003.

My xml looks like this:

<w:updateFields />

Any suggestions?