1. Add a new TXT record in DNS Toolbox.
  2. The Name should be the "_domainkey" value in the file.
  3. The Value should be the "k=rsa; p=[key]" value in the file.
For more information on obtaining the DKIM keys, please reference How to add DKIM Signature to Outgoing Email from NetCommunity, Online Express, or eTapestry.