Hi!
What about macro @USERID ?
In my script, working about 5 years (on w2k too) I'm using the following:

;Variable section
$homesrv="MyServer"
$homedrv="u"
: ......

; Drive mapping
$resource="\\$homesrv\@USERID$"
$drive="$drvhome:"
use $drive $resource

I prefer hidden user shares to avoid paging the hundreds of directory names.

Hope, it helps.

Regards,
Gennady