I've been using a RAID5 software raid for a while now without any hickups. As I needed more SATA ports I ordered a Highpoint Rocketraid 2320 (8 SATA ports) which arrived today. Now the problem is that it I can't seem to use the existsing array with the new piece of hardware.

The software raid was created using mdadm and consists out of 4 drives. When hooked up to the mobo SATA ports or a Promise TX4 card the drives get recognized as sdb, sdc, sdd and sde. But attached to the Rocketraid no devices are assigned. The Rocketraid sees the drive as uninitialized and won't do anything except initializing the drive and thus destroying the data on disk already
When hooking up a single non software raid drive it is assigned a device and I can mount and use the disk without problems. Tried this with multiple non raid drives and all are recognized as legacy drives.
So it's just the existing software raid I can't read. Any clues to how I can maintain the existing data and just continue using mdadm? I don't care for hardware raid, it's just the extra 8 SATA ports I'm interrested in. And the existing data offcourse.

Is this a normal behaviour for a highpoint card? Have I missed something? What could be the problem?

The system is running Debian testing with the latest kernel ( Compiled the latest highpoint driver, combined with build-in hpiopt driver.