HP HDD BackPane kit

[denniswier]

PartNo: 445985-B21
ManualRev: Sept 2007 (First Edition)

Im running a DL160G5 server with the hdd backplane described as above.
But is was wondering what use part: 450219-001/SpareNo: 452337-001 is for?
i also have 2 hdd hot-swap brackets attached to it, and no leds are working.

in the manual it states: 'Header for backplane aligns to backplane inter-connection'
so to be short, and to the point:

where can i attach this cable to?
and why are my leds not working?

thnx, denniswier