The class (slstcore.h) lists these colors and functions to change them:

COLORREF m_rgbText;
COLORREF m_rgbTextBk;
COLORREF m_rgbSelText;
COLORREF m_rgbSelTextBk;
COLORREF m_rgbDisabledText;
COLORREF m_rgbIconBk;
COLORREF m_rgbSelIconBk;
COLORREF m_rgbToolTipBk;
COLORREF m_rgbToolTipText;

However when the control in not active/ no focus, the selected item always show black text on white. None-of the above colors have effect on this.