Forecast data in APO

Hi,

I would like to know is there any other place we can store forecast data other than planning books in APO.

I wanted to use the BAPI 'BAPI_PBSRVAPS_GETDETAIL2' to pull the foreast details but this requires a planning book .

but my client does not use planning book to store forecast data. so, i would like to know what is the other place to store the forecast data and how we would fetch it?

thanks for your help