QTR-Quadtone RIP

Hello,
      I have just started trying quadtone RIP and I have tried to make 
my first profile for my EPSON R2400 which is loaded with the standard 
inkset.  In the ink descriptor file I have set the density values for 
the light black and light light black inks (measured using a 
spectrophotometer) and have set all the other inks to 'not used'.

When I print out a test strip (the 21x4 random) and analyse it with my 
spectrophotometer I can see that the colours are not neutral (when 
converted to RGB there is quite a lot less blue than the other two 
channels) and the print visually has a brownish tone.

Is there something else I need to do to prevent the colour inks from 
being used other than setting them to 'not used' in the ink descriptor 
file.

Apologies if this is all in a FAQ somewhere.  If you could point me to 
it that would be great.

Regards, Bill Brandt