RelativeLayout xaml ConstraintExpression property

My biggest problem with doing xaml ConstraintExpressions is that I can't get the right edge of objects. Is there a property / way to do that?

Something like "right" or "X+Width" or "Bounds.Right"

RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToView,
                                                  ElementName=locListLabel,
                                                  Property=Right,
                                                  Constant=5}"