Here are the specs on the controller from Compaq.
RAID ADG (Advanced Data Guarding) delivers higher fault tolerance than RAID 1, while keeping capacity utilization high, like RAID 5. RAID ADG protects data from multiple drive failures, while only requiring the capacity of two drives to store parity information. This higher level of protection is ideal where large logical volumes are required. (This feature is available on model SA-5304/128 and is available as an option to other SA-5300 models.)
High-performance, Fifth generation architecture offers the new hardware RAID engine, and a new performance memory architecture for increased performance over previous controllers.
Modular, easy-to-upgrade design lets you optimize performance and increase capacity as needed, from two to four channels and with 32-, 64- or 128-MB battery-backed Cache.
Ultra3 SCSI technology delivers high performance and data bandwidth up to 160 MB/s bandwidth per channel.
Up to 4 channels provide the highest storage capacity per PCI slot in the industry.
Mix-and-match LVD SCSI compatibility protects your investments and lets you deploy drives as needed.
Battery-backed Cache protects cached data in the event of a power outage, server failure or controller failure, and redundant, replaceable batteries take that protection even farther.
64-bit, 66-MHz PCI interface boosts bandwidth up to a 533 MB/s total transfer rate.
64-bit memory addressing supports servers with greater than 4 GB of memory.
Online Management Features: Online Capacity Expansion, Online RAID Level Migration, Online Stripe Size Migration, Online Spares (Global), User Selectable Read/Write Cache, User Selectable Expand and Rebuild Priority
So as you can see LOGICAL DRIVE EXPANSION IS NOT AN OPTION..I do hear that it may be added with the next revision of ss 5.0 with the firmware update and new acu this maybe a possibility.
