Trouble getting serial support for "Live CD" in 9 installer

[Adam McDougall]

I often use the serial console on my servers through ILOM remote console 
access to install FreeBSD because it lets me cut and paste commands into 
a live shell from install media.  Back with FreeBSD 8.x and previous, 
the console worked as a dual console between the redirected VGA/keyboard 
console and serial, all I had to do was drop to the loader prompt at the 
boot loader menu to enter:

set console=comconsole
set boot_serial=yes
boot

 From then on, the VGA console was ignored until I rebooted.  But in 9.x 
(currently trying 9.0-RC2 from the usb image), I have to interrupt an 
earlier loader to use -h or -D to enable serial(dual) console support at 
all.  I then enter the two variables above as I usually do, then specify 
my terminal type (xterm), then choose "Live CD" which prints:
Updating motd: /etc/motd is not writable, update failed.
Configuring syscons: blanktime.
Starting cron.
Starting background file system checks in 60 seconds.

Wed Nov 23 19:03:02 UTC 2011

but then it prints the FreeBSD banner and spawns the login: prompt on 
the VGA console instead.

Is there something else I can set during the boot process to make this 
work?  I could try modifying the configuration on the usb image to suit 
my site but this is more modification than I required in the past and 
surprisingly different.  Please let me know if I can provide more 
information or help in some way.  Thanks.

If I don't hear back in a few days or so, I'll make a PR.