Jim,
DH98MC? No such board...
On DH67BL, there are actually two SATA ports that support eSATA, one external (on the back panel) and one internal. Here are the chipset port assignments:
SATA0 (6G) Blue SATA Connector 1
SATA1 (6G) Blue SATA Connector 2
SATA2 (3G) Black SATA Connector 1
SATA3 (3G) Black SATA Connector 2
SATA4 (3G) Red SATA Connector
SATA5 (3G) Red eSATA Connector (Rear Panel).
Bottom line, look for red connectors...
...Scott