Retrieving FreeBSD src for ia64

Hi list,

I would like to install IA64 version of FreeBSD in IBM xSeries 206/306 or a Dell Server (still looking for a suitable model number for this), so I downlaoded a IA64 version of FreeBSD 5.3.

Since I need to rebuild the kernel source to stable with customized additonal options added in the kernel configuration file. I want to know which options need to be added to enable IA64 support? As I also need to download the source RELANG_5 for IA64, I also want to know how to pull out all the IA64 codes from the entire src? Currently I have the following supfile used for download the i386 source:
*default host=cvsup.ca.freebsd.org
*default base=/usr
*default prefix=/usr/local/ncvs
*default release=cvs
*default delete use-rel-suffix

Once this is finsihed, I use the following command extract the STABLE src from RELENG_5:

# cvs co -r RELENG_5 src

I m wondering how to do that same thing for IA64?

Thanks
Sam