Thank you for your help! I started to figure out somethings. Now my problem is implementing this code. It does not work in this way. I'm sure that Null_BRUSH implementation is right. Any suggestion?

Code:
void CDrawView::OnUpdateFillcolorTransparent(CCmdUI* pCmdUI) 
{
	CBrush brush;//I guess these are wrong
	pCmdUI->SetCheck(brush.CreateStockObject(NULL_BRUSH));//	
}
Code:
void CDrawView::OnFillcolorTransparent()
{
	CBrush brush;
	brush.CreateStockObject(NULL_BRUSH);

}