New Build - 2 WD VelociRaptors not detected

Hello, I've just completed building a new PC and after trying several different configurations with the 6 SATA devices (DVD, Bluray, 2 VelociRaptor 300BG HDDs, and 2 WD 1TB HDDs), I have run into the following.

My machine:

ASUS P6X58D Premium
Intel i7 920
12 GB RAM (Corsair Domintor)
BFG Nvidia GeForce GTX 295
Pioneer DVDRW SATA
Pioneer Blu-Ray Burner SATA
Win 7 Ultimate 64-bit (not used yet)
2 WD1002FBYS 1TB SATA HDDs
2 WD VelociRaptor 300GB SATA HDDs

Anyway, using the 6 SATA devices above, I can get my BIOS to recognize the 2 WD 1TB HDDs, the DVD-RW, and the Blu-Ray burner - but never either of the VelociRaptor drives!

No combination results in either of the VelociRaptors being found... Are they "special" in some way, or are they DOA you think? If I had only purchased one, I'd assume DOA and forget about it. But having them both not found by my BIOS, I wanted to check with someone who knows more about this than I.

I am using the current (0506) version of the BIOS. I started with just the essentials on the first test, mobo, CPU, 4 GB RAM, DVD Drive and one Raptor. Eventually I tried every combination of SATA cable to SATA port on the mobo. All ports and all cables work fine with all SATA devices EXCEPT the 2 Raptors... The mobo has 6 SATA 3.0 Gb/s and 2 SATA 6.0Gb/s connectors. I tried all of them, even the 6.0Gb/s. They are all working fine (except of course with the Raptors).

I've tried settings on IDE, RAID, and AHCI - same results.

Ideas?

Thanks in advance all....