I just saw that David Harrison pointed out on another thread that the NG software downcoverts the color to 16 shades (if I read it right). It is the tread about ? color TSU3000.
"The fact that you can import colour bitmaps into Prontoedit NG and it retains the colour on the editing screens and downconverts when it sends it to the remote or the emulator may be a hint that a colour version is eventually coming."