ping from other interface

Hello, I've never tested something like this before,

I want ping from the second or other interface that is not the main interface. But the output is allways the main interface venet0:0

I get this warning:

# ping -I "venet0:4" google.es Warning: cannot bind to specified iface, falling back: No such device PING google.es (173.194.112.55) from MAIN.IP.INTER.FACE venet0:4: 56(84) bytes of data. 64 bytes from fra07s28-in-f23.1e100.net (173.194.112.55): icmp_seq=1 ttl=55 time=30.0 ms

it's normal in OpenVZ?

Thanks!