Custom Attributes in search, specifically message direction

EV and DA are v904 for us.

http://www.symantec.com/business/support/index?pag...

On occasion, we need to search based on the direction of the message; specifically, external outbound messages. I'm trying to use it this morning and it's capturing messages that are internally sent. We have multiple internal domain names and I cannot find where in Enterprise Vault or Discovery Accelerator where to specify which domains are internal.

Thanks for any input!

Aaron