How Do I preserve lvm1?

I'm trying to install SuSE 9.2 using autoyast. I have a a cluster of SuSE 8.1 systems that were installed with a different installer. They each have one filesystem in an lvm1 logical volume that I really want to preserve. If push comes to shove, I can restore the data, but it would make my upgrade very time consuming. No matter what tags I set in the control file, my pv's,vg's,and lv's are erased and then re-created. Is there a way to prevent this? Brian