Installing FreeBSD from a disk partition

[J F]

I had FreeBSD 7.1 running on my machine and wanted to do a fresh install of 
7.2. Having two hardrives available, I created a small bootable partition on 
the second hard drive and copied the contents of the iso file onto it. I was 
able to boot into the installer just fine. In the media selection I specifiy 
"File System". But every path specification I try does not work. When 
commiting it just say it can't find the files. How do I specifiy that the 
files are on this boot partition?

Thanks for your help,

Jon