I'm not a good one to ask about this because I had problems with my external & LW also. Perhaps someone else might have some ideas.

Just storing should be the only change you'd need to make. Previous threads on similar topics (exluding the external):
(a) How to Change download location (click on link), __ (b) How to Change download location (click on link) (specific for folders),
(c) How to move downloads to new location