POS Forecast Report

I have this report , where I have to bring the POS and forecast . I have a multi cube on POS and Forecast cube . Now I have to bring <b>52 weeks of POS Qty in the past</b> and <b>52 weeks Forecast Qty in the future</b> .

My POS cube has 78 weeks data and the forecast has 52 weeks data.

But I am not sure how to make that represent POS Qty of the past and the Forecast Qty of future.

Thanks