boot.conf in alpha port

Hello,

I installed OpenBSD 4.0 in an Alphastation 200.
I installed OS in ide disk (with PCI/IDE card)
The installation works fine, but the disk is not display in >>> prompt

I try to use the file boot.conf (as in i386 port) in a floppy, but it  
does not work.

If I install in SCSI disk, I can boot from this disk (see as DKA100  
in the >>> prompt)

How can I boot from the floppy or the CD and load the kernel in the  
ide disk (the file boot.conf do that in i386 ports).

Thanks,

Emmanuel