I'm using XP Pro SP2, Avast! 4.7 & Thunderbird (it says 1.0.6 but I thought it was later) and am not having the same experience.
When it arrives, I can see the message in my inbox (including the attatchment icon). I would have expected Avast! to have at least notified me by now, but nothing.
Are you using IMAP or POP? If IMAP the message header and attachment icon will appear but the EICAR test file will not be detected until you actually open the message, just as you describe.
When I then open the e-mail, the attatchment suddenly disappears, and I am simply left with the text of the e-mail.
This doesn't sound right. If the Avast Internet Mail provider is in Silent mode, with General answer No, the attachment will be stripped and quarantined but you should still get a notification in the message like:
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avast! Antivirus: Inbound message INFECTED:
\eicar.com#1825043748 (EICAR Test-NOT virus!!) Moved to chest
Virus Database (VPS): 000740-0, 13/05/2007
Tested on: 14/5/2007 14:04:07 PM
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