It is true, the solution is to change the attribute "point":
<ma-point-values point="point1"

by the attribute "point-xid" with the XID of the data point you want to draw:
<ma-point-values point-xid="myXID"

Could be a good idea to add an example to the "Mango Dashboard Examples" with this option to draw a chart.

Thanks.

 <!-- Get point values -->
 <ma-point-values point-xid="hallsFanInletAirTemp" point="inletAir"></ma-point-values>

 <!-- Create a way to manupulate point values to 12 previous hours and update.  In this example, I am getting previous 12 hours at a 1 minute average.  You only have to do this once -->

<ma-now update-interval="1 minutes" output="to"></ma-now>
<ma-calc input="to | moment:'subtract':12:'hours'" output="from"></ma-calc>

<!-- Manipulate the actual values of the point.  This code can be multiplied for as many points as you want -->

<ma-point-values point="inletAir" values="inletAirValues" from="from" to="to" rollup="AVERAGE" rollup-interval="1 minutes">
</ma-point-values>

 <!-- Display Chart -->
	<ma-serial-chart 
                style="height: 500px; width: 100%" 
                series-1-values="inletAirValues" 
                series-1-point="inletAir" 
                series-1-color="green" 
                series-1-axis="left"
                series-1-type="line"
                legend="true" 
                baloon="false"
                options="{
                    valueAxes:[
                        {
                            axisColor:'black', 
                            color:'black', 
                            title: 'Temperature °F', 
                            titleColor: 'black', 
                            minimum:-40, 
                            maximum:140,
                            fontSize:26,
                            titleFontSize:26,
                        }, 
                    ]
                }"
            >
            </ma-serial-chart>