Larry -
I not sure you can specifically perform this with your script.The HOMEDRIVE, HOMESHARE and HOMEPATH values are defined within the Users domain profile. Simply trying a SET command from the command prompt will not change these (at least not in my quick tests).
However, you could try mapping a drive letter to a specific folder, then changing the "HKEY_CURRENT_USER\Environment, HOMEDRIVE" value to reflect this new letter (at least within WinNT/2K systems).
However, even if this change works, it is really a kludgy method. If yours HOME directories are not the proper storage location for files from an application, you should check the registry values for that application to see if you can reset the default save location within KiX.
For example, in Win2K change the "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders, Personal" to have the default storage locations for "My Documents" be something other than the Offices' default.
Lastly, if your users HOME values are incorrect they are more properly set within User Manager or some script to automatically update the values on the DC, not on the client.
Bill