老实说，我根本无法理解您要尝试执行的操作。

To be honest I can not understand at all what you are trying to do.

您取回了SPC文件，该文件只是带有证书的＃PKCS7 der编码。

You got back the SPC file which is just the #PKCS7 der encoding with your certificate.

您还拥有私钥。

所有您需要做的就是将证书导入pkcs12密钥库，以获取带有私钥的签名证书。

All you need to do is import the certificate to the pkcs12 keystore to have the signed certificate with your private key.