printing b&w with Epson Stylus Color 760

[Tomas Davidek]

Hello,
  my printer (see subject) has two ink tanks - black one and color one. The CUPS I am using now (version 1.4.4) has for this printer only the ppd "CUPS+Gutenprint v5.2.6 (color, 2-sided printing)". It prints ok, but always uses colors. I wonder how can I force CUPS to print in b&w? I could not find such a driver....

Or can I just modify the ppd, e.g. changing
*DefaultColorModel: RGB  -> *DefaultColorModel: Gray/Grayscale
Unfortunately, there are several similar items in the ppd, so I am not sure what exactly should be changed. Moreover, if this is the right way to go, how do I make sure the b&w printing really uses the black ink tank and not the color one?

Thanks a lot for any hint,

best regards
                  Tomas Davidek