Hi,
If you are talking about PDF sign (embedded signature) then I think you require PAdES signing. PDF reader understands embedded PAdES signatures and does not under stand CAdes-BES signature.
It is not clear to me the level of implementation you have and what is the exact requirement, So I am mentioning a tentative bid value for 15 -16 hours of efforts.
If you are interested ping me to further discuss the actual requirement.