Hi Azam
I not sure if really require BAPI.
You should create flat file with details and upload into APO BW cube.
Please find below the link which will provide you to upload he data into APO BW PSA from where you can load the data into APO BW cube.
Once you have data into APO BW , you can release the data from APO BW cube to SNP. I would request you to check or get help from BW/BI consultant for this actvity.
Please let us know if this information helps you.
Thanks
Amol