Chris Lord one of the PMs gave an insite into this on the technet forurm @ http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=2880423&SiteID=17 .
Global Package Volume
\Users\Public\Documents\SoftGrid Client\AppFS Storage\<Pkg+GUID>\GlblVol_sftfs_v1_S-1-5-20.pkg
Contains any application-specific data that is modified by a system process. The well-known SID for system is appended to the volume. In SoftGrid 4.0 and 4.1, this volume was used for all modified application data; in 4.2 and 4.5 modifications are separated into those made by system processes such as the Listener, and those made by user application processes. User modifications go instead to the Application Data Isolation Volume. The global package volume also contains the virtual environment configuration for system processes.
Global User Volume
Contains new or modified user-specific data from a system process that is not associated with a specific user context but is associated with a specific package.
Application Data Isolation Volume
\Users\Public\Documents\SoftGrid Client\AppFS Storage\<Pkg+GUID>\GlblVol_sftfs_v1_<SID>.pkg
Contains application-specific files that are modified by any user process in the virtual environment. The SID of the user is appended to the volume name to uniquely identify it.
User Package Volume
\Users\<User>\AppData\Roaming\ SoftGrid Client\<Pkg+GUID>\ UsrlVol_sftfs_v1.pkg
Contains user-specific files that are modified—or new files that are created— by any user process in the virtual environment. This volume also contains the virtual environment configuration as modified by the user.
The state management is different in 4.5 than in prior releases to provide better isolation between users as well as application packages. Any question that you have on this subject ping them up the forum for Chris to answer!