Digital BW, The Print

I own an Epson 4880, which I have used only with MK ink.  

I would like to switch to PK black ink, but cannot find the black-ink-switching-kit that came with the printer.

I haven't been able to find it on the Epson site either.   Is it there?  Where?  Is there any other source for a replacement?

Thanks.

Myron