VS 2010 MSChart - Add second series

Hello,
on my MsChart i have the first series with dates on X axis.
I want to add another series where to add points depending on values on X axis. If i want to add the date "2013-01-01" with value "200" i want this to show a point right above the value "2013-01-01" on my first series.

I tryed like this

Chart.Series(1).Points.DataBindXY(date_values_in_array, value)

The "value" shows in correct position but the "date_values_in_array" shows always near 0 position, no matter what date value i choose.

Any ideas?
Thank you!