Found a solution changing the plugin (textcolor). If there is a better way please be free to post it.
I added additional colors to the colorpicker. The Color #FFFFFe (near White) i marked as NO COLOR and changed the plugin as shown.
function onPanelClick(e) {
var buttonCtrl = this.parent(), value;
if ((value = e.target.getAttribute('data-mce-color'))) {
buttonCtrl.hidePanel();
value = '#' + value;
buttonCtrl.color(value);
if (value == '#FFFFFe') { //Changing the value to -1 causes deletion :-)
value = -1;
}
editor.execCommand(buttonCtrl.settings.selectcmd, false, value);
}
}