LTSP on AMD64 with i386 client

I have installed LTSP on my dual opteron "breezy" box following the 
ThinClientHowTo.  It was very easy and seems to have worked.

My client PC begins the boot process but then fails because it is a i386 
machine and LTSP is setup for AMD64.

I googled and found a link that says an AMD64 machine can act as an LTSP 
server for a i386 Client by calling ltsp-build-client with the 
--architecture flag set to i386.

However these instructions do not seem to work as it is not a valid flag 
for the script.  I had a look at the script but I could not figure out 
how to modify it to install other architectures.

Is there a way to do this?