Digital BW, The Print

I am brand new to digital photography and just picked up a copy of 
Photoshop 7.0 (Actually I am pre-brand new -- I haven't even 
received the program yet). My understanding is that MIS variable mix 
inks don't work with PS7. Is this true? If so, what happens to the 
tone color when they are used? Would it be possible to correct this? 
I'll be using either an Epson 1280 or 890.

Mike