I had no problem configuring disks in Solaris x86.  I did however have a problem with the webstart installation.  I recomend booting off the Solaris 8 Software disk 1 of 2 CD.  The Solaris 8 Installation CD is useless (IMHO), I don't use it when installing Solaris Sparc either.  Durring the partitioning portion I was asked to FDISK teh drive and laters given the option to manually configure the drive.  When you manually configure teh drive you use MB for the size of each partition.  If you are still having a problem let me know.

Dusty

"Linux is for people who hate Windows. BSD is for 
people that love unix."