How to get SHIFT+TAB worked as tab-back functon? [1]

I usually use vim and map SHIFT+TAB as tab-back.
That is \033[Z.
I cann't map SHIFT+TAB in custom keymap.

Program Ver. : Xshell 4

Currently you can't map controls key combinations such as SHIFT and Tab key. We will consider adding this feature in the future.

Thank you for your feedback.

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