On Mon, 7 Feb 2005 10:57:33 -0300 (ART), Homero Thomsom
<homerothomsom at yahoo dot com dot ar> wrote:
> Hello.
> 
> I need to configure two Dynamic DNS accounts. Are two
> different accounts, different user and password.  Each
> one of those accounts has manifold dominions.
> 

You can't do it on m0n0wall itself, but this might help. 
http://m0n0.ch/wall/docbook/thirdparty-ddclient.html

-Chris