Different av vendors are using different names for viruses.
Bagle.az as Panda calls it is known by Avast as Win32:Beagle-AL [Zip]
W32/Bagle.az@MM as McAfee calls it is known to Avast as Win32:Beagle-AO [Wrm]
Have a look at
VGREP, but keep in mind that VGREP is not up to date with all the names.
Stop being surprised, Avast does recognize the malware
