I do not know if anyone is working on it, but just thought I would raise the issue. The interior of real U-Boats was painted white:
from:
http://www.uboat.net/gallery/index.html?gallery=U995C
this was in SH4 as well:
and here is the thread where the issue was discussed:
http://www.subsim.com/radioroom/showthread.php?t=162477