Well, I just follow the steps below:
1. In the cPanel->Security->SSL/TLS Manager->Private Keys (KEY), I generate my private keys.
2. In the cPanel->Security->SSL/TLS Manager->Certificate Signing Requests (CSR), I generated a CSR.
3. In the StartSSL Website, I uploaded my private key and CSR to get a certificate file.
4. In the cPanel->Security->SSL/TLS Manager->Certificates (CRT), I uploaded my certificate file.
Don't think it will work before you assign a dedicated IP to me, right?