PowerConnect 6224 connector to RPS-600

This is probably the dumbest question I ever asked: I sent a technician to install on our PowerConnect 6224 a recently purchased RPS-600. The technician calls me back and tells me that the connector for the DC IN on the switch is not there (See attached image)

I tried looking on the manual and on optional accessories but could not find any information on a DC IN module. Am I right in my guess the connector is just hidden behind the cover? or is there some optional module I should buy for this (I already have the RPS-600 and cables)?