Most good auto paint suppliers can do the same thing as Sears, Lowe's, Home-depot and others do with the computer paint analysis software.
Take your front panel (easiest to detach) in to the auto paint store with this capability to have the white color matched (call around to see who has this capability first) ...
Do not bother getting Sears or Lowe's etc.. to do it, as the house base colors and the auto paint base colors are all different
Failing getting a color code, or having any auto paint suppliers in your area that can computer select the color......... find a crash repair center and find the one or two auto painters in your area that has been doing it for decades...you would be amazed at how many of them can tell exactly what brands and mixes will be so close you can not tell the repair was made.... these are the old birds that have learned how to adjust for fade and deterioration even when they have the factory color code...
Be sure to tell them what color the White is going on top of....!!!