Fake IRS Support mail,avast cant catch

these malwares are occasionally sent to my yahoomail(a document-type zipped malware) and avast and norton cannot catch it
i have submitted them but they change their patterns and avast will miss the new type but eset and avira can get it
be carefull about the subject:
IRS NOTIFICATION LETTER
these are the examples:
http://www.virustotal.com/file-scan/report.html?id=4ba5eb3e686e3072f2b1c83e333d12b9bfda9c04554238da3b99e1742e50a084-1309879622

http://www.virustotal.com/file-scan/report.html?id=2bd26619a5c4bbd13cce3d42608f97cf5042b272991de6fa0c68c203e8088b59-1309855024
see these links:
http://www.faravirusi.com/2011/06/19/solutie-irs-notification-letter-virus-prin-email/

http://www.scamtrends.com/irs-notification-letter/