FB01/FB02 attachment download

Hi members,

I have a requirement is like, I want to download the all attachments are in FB01/FB02 transaction (GOS-> attachments) and attache/club into on Invoice PDF output, So can you hep on this,

Note: Invoice PDF is available and attachment/club logic is available but download the all attachments from FB01/FB02 logic is need.

Please provide some clues also fine with me..

Thanks,

Mahesh