I know my case maybe specific but for a paid application, it should be possible. My phone is always connected through a VPN, the same VPN is hosting the owncloud server. So I have to enter the ip 10.8.0.1 to connect to owncloud in https. When I do, I have a message saying "secure connection is redirected through an unsecured route" because the certificate is for the fqdn and not the ip address, but I can't enter the fqdn because the route can't work that way.
And here I am, unable even to try the connexion. So I can't use the service AT ALL.
Simply because my server doesn't have http enabled for security purpose.
Anyway, I found a solution. If you encounter the same problem, you have to edit the /etc/hosts of your phone or gateway so that the ip is linked to the FQDN. In my case I had to add : 10.8.0.1 mysite.com
That way owncloud can recognize the https as trusted.