I try to bind the underscore ("_") character to the shift+space key-combination in Xterm terminal.
I put these lines in the .Xdefaults file:

XTerm*VT100.Translations: #override \n\
Shift<Key>space: string(_)

but the shift+space only gives me a normal space....
BTW alt+space works (!) but I would like to use the left shift key....
Please help me
Best regards,