Digital BW, The Print

Got MIS EZ ink and empty cartridges today, and have filled the Y, M, C. 
But on my High capacity Black cartridge there are no hole for filling 
the ink.
There are only two vent holes in the sponge section and of course the 
exit port. Am I suppose to fill from one of the vent holes, directly 
into the sponge,
or from the exit hole also in the sponge section. Any advise 
appreciated.

thanks,
danny