You can extract the true dates from the PRICE array and use them as a LABEL along the X axis on the sequential candlestick chart:
var plt = formPlot.Plot;
var candlesGraph = plt.AddCandlesticks(prices);
candlesGraph.Sequential = true;
double[] tickPositions = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
string[] tickLabels = prices.Select(price => price.NameOfDateField.ToString()).ToArray();
plt.XTicks(tickPositions, tickLabels);

You can generate sequence numbers at the same time as filling in the PRICE array.
The only drawback will remain - crosshair will show the wrong date.
In addition, you will have to convert the display limits from numeric to DateTime for plt.SetAxisLimits(xMin, xMax);