mayday, if you can zip and password protect ('virus', will do) the suspect file and send it to virus @ avast.com (no spaces).
Give a brief outline of the problem (jotti detection, etc.), the fact that you believe it to be an undetected trojan and include the password in the body of the email. Some info on the avast version and VPS number (see about avast {right click avast icon}) will also help.