DateTime Axis with label dates not 1 January each year

I am creating long-term forward-looking graphs at future dates e.g. with the data points being annually from 30 June 2014 for the next 20 years, and the DateTime axis always defaults to showing me 1 Januaries on the x axis.

Is there any way to specify that the x axis labels should instead be every 30 June (or indeed any other date in the year)?