This workaround works most of the time. It uses eclipse's 'smart insert' features instead:
- Control X to erase the selected block of text, and keep it for pasting.
- Control+Shift Enter, to open a new line for editing above the one you are at.
- You might want to adjust the tabbing position at this point. This is where tabbing will start, unless you are at the beginning of the line.
- Control V to paste back the buffer.
Hope this helps until Shift+TAB is implemented in Eclipse.