I found this article and tested this succesfully.
You need to have following application to make this work.
1. Microsoft Word Viewer 2003 (12.5 MB)
http://www.microsoft.com/downloads/details.aspx?FamilyId=95E24C87-8732-48D5-8689-AB826E7B8FDF&displaylang=en
2. Then try to open a docx file using this it will ask to install a compatability pack for 2007 files install that (27.5 MB)
once you installed that you can view docx using word viewer 2003 but you can't edit.
Now right click on the docx file
and select Microsoft Open XML Converter. Then it will automatically open it in Openoffice from which you can save file as doc file and work on that.
Source: http://www.oooforum.org/forum/viewtopic.phtml?t=52499&highlight=docx+read
