How to update an amd64 machine with raid?

[David Wetzel <dave%turbocat.de@localhost>]

Hi folks,

I have a amd64 box currently running NetBSD 4.0 which I would like to  
update to 5.0.1
It seems like it always wants to boot from the raid, not from the cd.
I have (paid) access to a Lara console if I want, but no physical  
hands on the box because I am on a different continent..

Is there a secure and tested way of updating the system?

Like placing all install files on a new directory,
having a custom rc boot script that does the same like the update  
would do and reboot?

Thanks!

Dave