AutoSSL for subdomain on different server?

Hi all! I have a VPS that i want to use as a cloud test in my reseller domain (the reseller is in another server). So i've created the subdomain in cPanel and modified the subdomain's IP in WHM and it works well. Now the problem is that i want to use SSL in this subdomain and I think that cPanel can't do anything for this, it's right? There's a possibility that cPanel can use FTP or something to modify the directory in the server for the autoSSL verify code? Or at least can I copy manually the folder? Thank you in advance