Prob. installing SCSI HD with Partitioned IDE

[??]

I'm running under Win98 with an 8Go IDE drive partitioned in 4 logical
drives of 2Go.
I also have a SCSI Plextor 32X CD-R and a SCSI Yamaha 4426 CD-RW on a Tekram
DC-390U.
IDE Partitions are C,D,E and F letters, CD Drivers are G and H.

I've bought a 4Go SCSI Seagate HD and want to install it, but not as a boot
disk.
The installation is OK, I format it under Win98 with no problems. It has the
D letter, other periphericals becoming E,F,G for logical drives, and H,I for
CD Drivers.
But, when I reboot the computer, I have an unusable D drive (it seems to be
my SCSI HD but can't be readed, written or formatted), IDE partitions are
C,D,E and F, and my SCSI HD is the G drive!

What's the mess with all that shit??

Thanks for your help!

PS : Tekram card is recognize by Win98 but driver must be upgraded before I
can access my SCSI peripherals, so I think I can't make my SCSI drive my
boot drive