QTR-Quadtone RIP

Hi everybody,
i'm trying to print with my Epson R265 (european R260 version) and my
new Black and White Refill kit for Epson R260 of RCN Ink with Eboni
Black. It was supposed to be a Neutral black for matte paper.
I did many test with different curves like MK-Epson-Matte-HW-BO,
MK-Moab-Entrada-Nat190-BO, MK-PremierArt-MatteBW-BO and Epson Archival
Matte Paper (192 g/m2).
The result is a print warm near a sepia tone. 
My question is : what's wrong? what can i do to print a cool neutral
black ? What curve am i suppose to use ?

I use Quadtone RIP with my Mac Leopard and print with photoshop CS3.

I hope i exposed my problem clearly.

Thanks in advance.

Paolo