how to change colors in evolution when using xfce 4.8 ubuntu 12.04

[user1]

How to change the colors in evolution when using xfce 4.8 in ubuntu 12.04.
When I use unity everything works ok.
When I switch to xfce - to reduce cpu power consumption I get black 
background color with darkblue text in window where new mails is shown 
which makes it very difficult to read text.
Others seems to have same problem.
I have asked both in evolution -and xfce mailing lists for a solution?