From the above document it says
if the folder does not exists it will create the folder only in C drive
https://www-secure.symantec.com/connect/forums/change-location-gup-sharedupdates
Only the installation files will go on D drive , folders like liveupdate and shared folders will be on C drive
my virtual lab does not have D partition so I cannot test it as of now, You can give it a try and update us.