Don't know, if you have special needs of your php install I would suggest uninstalling it through YaST and then compiling it from source. It's really not very difficult and it will give you much more flexibility with the install.
Having said that, I would be very surprised if the default SuSE isntall would not have session support enabled. Have you checked phpinfo() to make sure that it is disabled? Also, check in your php.ini to make sure it's not disabled there (it may be enabled in the install just disabled in the .ini)
