Asus L5800C with Samsung SN-802

[qanda]This thread is about the Asus L5800C-com/P2.66/512mb/40gb. Click here to see full specs[/qanda]My original dvd reader (Toshiba SD-R2312) is out of order.
I try to install a DVD writer Samsung SN-S082H/BEBE but it is not seen by the Bios at all.
Only my Hard disk is seen as secondary.
How can i reverse ATA on my new DVD (i cant find anything about that on Internet) ?

Thank you for your help.
Best regards