On the "My Statement" page, my flights with several sectors over more than one day get credited on the day of the last sector.

Example: 8 March 2014, Europe West (ZRH) to Subcontinent East (DAC) and the miles. The breakdown shows the first sector ZRH-DXB on 7th May, DXB-DAC on 8th March. The total for both sectors gets credited on 8th.

This pattern is followed everywhere, so I assume you will get the whole leg credited in April. You could call them to try and split it up.