Import private key from .p12 file to sign an XML file with XAdES-BES Signature

[jhcueva]

Hello everyone I'm using xadesjs specifically the XAdES-BES Signature, to sign a document that will be validated by the entity to manage the payment of Ecuadorian taxpayers. I've been following the steps of the documentation.
First I have lo load the private key in order to use the function SignXml(xmlString, keys, algorithm). For that I have implemented the following code:

const fs = require("fs");
var { Crypto } = require("@peculiar/webcrypto");
const xadesjs = require("xadesjs");
const { XMLSerializer } = require("xmldom");

const crypto = new Crypto();
xadesjs.Application.setEngine("NodeJS", new Crypto());

// Hash and algorith from the example
const hash = "SHA-1";
const alg = {
  name: "RSASSA-PKCS1-v1_5",
  hash,
};

function preparePem(pem) {
  return (
    pem
      // remove BEGIN/END
      .replace(/-----(BEGIN|END)[\w\d\s]+-----/g, "")
      // remove \r, \n
      .replace(/[\r\n]/g, "")
  );
}

function pem2der(pem) {
  pem = preparePem(pem);
  // convert base64 to ArrayBuffer
  return new Uint8Array(Buffer.from(pem, "base64")).buffer;
}

// Set the path of the  .p12 file
const path = require("path");
const p12Path = path.resolve(__dirname, "cert.p12");

//Read key
const keyPem = fs.readFileSync(p12Path, { encoding: "utf-8" });
const keyDer = pem2der(keyPem);

//Retrieve the key to sign the document
const key = xadesjs.Application.crypto.subtle.importKey(
  "pkcs8",
  keyDer,
  alg,
  false,
  ["sign"]
);

But I have the following error:

            throw new Error(asn1Parsed.result.error);
                  ^

Error: End of input reached before message was fully decoded (inconsistent offset and length values)
    at Function.parse (/home/baeto/Documents/xades/node_modules/@peculiar/asn1-schema/build/cjs/parser.js:14:19)
    at Function.importKey (/home/baeto/Documents/xades/node_modules/@peculiar/webcrypto/build/webcrypto.js:863:54)
    at RsaSsaProvider.onImportKey (/home/baeto/Documents/xades/node_modules/@peculiar/webcrypto/build/webcrypto.js:1036:37)
    at RsaSsaProvider.importKey (/home/baeto/Documents/xades/node_modules/webcrypto-core/build/webcrypto-core.js:234:33)
    at SubtleCrypto.importKey (/home/baeto/Documents/xades/node_modules/webcrypto-core/build/webcrypto-core.js:1475:29)
    at Object.<anonymous> (/home/baeto/Documents/xades/index.js:42:47)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)

Any suggestions are welcome!