It's in Blackberry Server Configuration (on GW BES this is via the Start-->Programs-->Blackberry Enterprise Server --> ) on the Attachment server tab - from Config Option drop down list ensure 'Connector Configuration' is selected; you'll see a list of supported file extensions on this page, add the extension you need to the list. You can enable a file distiller and max file size by changing the drop down option to 'Attachment server'.
Check the Blackberry Server help file for file extensions for step by step instructions if you need more info.
Thanks for the help...
I was just asking how for my knowlege. Since I read it would not work. As I said in my post I was just thrown in administrating BES and more I can learn the better.