PDF Digital Signature pkcs7 java

I am using itext to sign the pdf document.

I will share the entire process with you for you to analyse.

First visual signature appearance is added to the document (But at this time signer name and other details is not present). Then document hash is generated and sent to e-sign provider along with eKYC-ID. Based on id they generate digital signature in pkcs7 format and send us back the same. Now we have to extract the signature and the user certificate and sign the pdf (Notice here, if we we try to add name to the signature appearance the document hash will change).

Please suggest any alternative if any to solve this issue using any pdf creation library...