Change to a bigger harddisk

Greetings,

I have successfully tried out the wonder of this small unit with an 
old Iomega 40G HDD and now I want to attach an 250G instead on port1.

As far as I have read I need to "Unsling" that new drive. 

Quote from the README:
"- Once you "unsling" to an external disk on a particular port (Disk 
1 or Disk 2), it is important that you keep that disk continually 
plugged into that same port whenever the NSLU2 is turned on. "

Now then I remove the original Disk 1 and attach the new one as Disk 
1. How do I make that behave as the original one?

If I just do: /sbin/unsling
As far as I understand this moves some files from the ramdisk to 
disk 1. But if I have done that before what is left to move?

If you know how to do this (it's probably obvious, but I am totally 
new to Linux, but know how to read. Meaning I just do EXACTLY as 
told...) then please help me.

Note: I haven't tried yet. I am afraid to brick this.

Regards
Teobald






[ Moderator Note: All static information is slowly moving to the Wiki at 
http://www.nslu2-linux.org ]