I see a few entries here about [making Shift-Tab work in vim](http://vim.wikia.com/wiki/Make_Shift-Tab_work), but none of them addresses the failure when it's in Cygwin, running at a Windows command prompt. In that environment, Shift-Tab works for me exactly like an unshifted tab, and my attempts at remapping have failed:

* `:imap <S-Tab> ^D` [ this is a real Ctrl-D, entered with Ctrl-V before it ]
* `:imap` [ typed Ctrl-V, Shift-Tab here; got a Tab character inserted ]

So it seems that the Shift modifier is being ignored. Any thoughts about how to proceed? Thanks.