have your own php.ini on shared servers. There's no file by default, so you may have to add it, and your .htaccess will need an entry to point to it.
. It sounds like it should be a standard part of PHP 5.3 and up, and maybe an extension for earlier versions... what version is your server running?
Note that shared servers do not allow background processes, so it is possible that OwnCloud is not allowed. You might want to check with LP support before you put a lot of time into this.