There is a way, you will need to do Custom Filtering. Please check out the Install and Configuring guide on how to set this up - under the Chapter: Custom Filtering and Properties. There are some registry edits that need to be made as well as the creation of an XML file which contains the rules for archiving.
For eg. the xml below will strip all WAV files before archiving:-
<RULE NAME="DeleteWAVs" ATTACHMENT_ACTION="REMOVE">
<FILES>
<FILE FILENAME="*.WAV"/>
</FILES>
</RULE>