File Type Exclusion, and Stop Subj insert of [avast! - SUSPICIOUS]

We have managed clients (4.6) communicating with the ADMN server (4.6.453).

Our voicemail is transfered into MSoutlook via Phone Switch (Nortel) with the software “Call Pilot”, when the message shows up in MSoutlook under the Call Pilot folder you can see that it is several kilobyte file, but when we touch the message to open it AVAST strips the file clean down to 0 kilobytes.

Without AVAST installed the Voice mail messages work just fine.

1.) Can we exclude a file type in ADMN via CUSTOM.ini settings, or any other ideas.
2.) Finally, how do We change the Insertion of the [avast! - SUSPICIOUS] tag, can we raise the spam counter setting or something else?