How can I add an Xtra HD to an IDE channel when....

My main "C:" 15GB GXP75 is on a ATA66 controler port on my BXMaster(440BX).


My problem.

I can now run a HDisk as a slave to my DVD Drive in my Setop Box.
This will allow me to stick as large a HD in there as I want and be able to play MPEG2/1 or Jpeg/mp3's....
For starters I'm trying to fire up an 800MB P75 HD I have.

To make it easy to copy files to the HD, I want to be able to connect it to my current BXMaster setup as another drive to which I can copy files and make directories...etc...Simple Eh!

Problem is, with my present setup and the boot disk routine I have, I cant get my PC to boot to its normal 15GB GXP75 on the U66 IDE1 port after I've put the 800MB on either Primary or Secondary IDE even if I set it only as the Slave (obivous of course).

I've tried changing the boot sequence but it still goes to the 800MB disk and says - non-system disk please change....blah...blah...
The other disk isnt getting picked up....

I cant put the 800MB as slave on the same IDE cable 'cause I'm using an 80pin on that main HD on the U66 IDE1, that's why I'm using the Primary/Secondary IDE ports on which I usually (and still) run my CD and CDRW.

Any trickery I'm missing here?