trouble with preseed partitioning

[dale at czexan.net]

Hello,
   Not sure if this is the right list to ask for preseed help, so  
please redirect me to a better source as needed.

   I'm trying to fully automate an ubuntu 10.4-amd64 desktop install  
in a unique oem install environment.  The install environment is the  
os install media are located on a small fat32 partition /dev/sda1 and  
the network may not be available during the install.  I am using the  
alt cd iso, a custom preseed, and the hd-media kernel/initrd.  The  
fat32 partition boots and autoexec.bat launches linld.com with  
kernel/initrd/kernel options which start the install.
   I can run install with preseed file but am always prompted to  
unmount /dev/sda1 (fat32 partition where install is launched from) and  
to verify changes to partition table (adding /dev/sda5 ext4 as / and  
/dev/sda6 as swap).  I have extracted the installer options with  
debconf-get-selections --installer > seed; debconf-get-selections >>  
seed and rerun the installer with this seed file, but am still  
prompted about unmounting /dev/sda1 and confirm partition changes.  Is  
there a way to preseed these choices so installer will run without  
user intervention?  Is there a list of all preseed commands/options?   
I have found some info on a debian d-i wiki and a few howto's but not  
a thorough source of preseed option/info.
   Thanks for any info that can help with my automation efforts.

Thanks,

dale at czexan.net