I was wrong, only the vncproxy method is returning null while sending the request to url below
/api2/json/nodes/localhost/qemu/111/vncproxy
It was OK on Proxmox2 but to make it work on Proxmox 3 I should change the localhost on the url to hostname of server
/api2/json/nodes/p11/qemu/111/vncproxy
Is there any way to make it work with localhost? I dont have hostname in that part of my code, lots must be changed
Regards