Question about snaking cable through Gitzo g1553 boompole
 

I just picked up a Gitzo Carbon Fibre G1553 boompole, which was advertised of being capable of snaking a cable through it (it didn't come with an internal cable). There doesn't appear to be any port hole at the microphone end of the pole for a cable, just a fitting which appears to be just the standard 1/4" screwhole.

Is there a hollow screw or something which is supposed to be used with boom poles to allow for the snaking of the cabling?

Thanks -