Setting a user system variable

Good day all. Here is the situation I find myself trying to solve. I need to be able to set the %HOME% variable on an NT 4.0 system prior to the user of that system logging on. For example:

The current value of the %HOME% variable, which is a system environment variable, is set to “c:”. I need for the user to have it set to “c”\home\username” when he logs on. I cannot, however use a logon script or enter it in an autoexec.bat file to set it. Is there a way to set this value from the command line or otherwise, when doing an NT install? Thanks.