If I start a new message, click the attach button and browse to the folder with all the documents. It seems docx don't appear, however doc files and pdf etc all appear. It does say "all files".

Using version 8.0.2 from 1/8/2011 and win7 64 bit, and msoffice 2007.

however I can go right through my computer to the folder and find the docx file right click it and send to mail recipient and it attaches fine then.