Thanks for all your excellent advice! I now managed to boot my DS3100 using
the 32M-diskimage file. Here's what I did:

On my i386 NetBSD machine:

#dd if=32M-diskimage of=/dev/rsd1d

[That "d" was the central mystery for me. It's obvious that I'm still not
grasping some issues regarding disklabels.]

Then I removed sd1 from the i386, changed its SCSI ID to 0, then installed
it in my DS3100. There, I issued the following command:

>> boot -f rz(0,0,0)netbsd

and viola! The machine booted!

Now to figure out what to do next to get a full NetBSD installation on the
machine.

What I have to work with:
	*another ST1480 HD (currently the drive of my i386 NetBSD machine). My
intent is to use this as the second disk for the DS3100.

So, what I assume needs to be done next is:
	*install the second drive in the DS3100 (rz1).
	[Note: this will destroy my i386 NetBSD helper machine.]
	*label that disk (going to need help here).
	*FTP the PMAX NetBSD distribution files onto rz0.
	*install the full NetBSD onto rz1 from rz0.
	*boot my DS3100 from rz1 and start configuring.

However, right now I have 2 immediate problems:
	1) the system on rz0 is "read only."
	2) I can't find any ftp facility on rz0.

Any ideas?

Paul.