Upgrade from RC1 to RC3 full install

[mrvanity]

Hello again!
I am very happy seeing pfsense progress  ;D

I have wrote done my setup and my only two minor problems here:
http://forum.pfsense.org/index.php/topic,16338.msg84899.html#msg84899

I am using the 1.2.3-20090517-2314 release so far.
Since RC3 is almost finished i am thinking of upgrading hoping that my small problems will be solved.
Since there is nanobsd being used now how can i safely upgrade to RC3?

Excuse me if this is mentioned again :(