Using second eSATA port for second DAS
Do you mean, an HP MSA 60 Array Enclosure? And for cables, you're probably referring to an external multilane SAS SFF-8088 connector.
If so, then depending on which HP Smart Array RAID controller you're using, you can cascade up to three additional MSA 60 shelves off of one unit by using one port as IN (4) and the other as OUT (5).
Cascading - The MSA60 has the unique capability of cascading up to 4 - four enclosures behind a single SAS port (depends on the Smart Array Controller).
(source: www1.hp.com)