I am unable to assign the profile using the ovirt api code, the following xml code is used for creating the nic

 <nic>
    <interface>virtio</interface> 
    <name>eth0</name>
    <boot_protocol>static</boot_protocol>
    <mac address='".$ip->mac_address."'/>
    <network>
     <ip address='".$ip->mac_ip."' netmask='255.255.255.0' gateway='".$ip->mac_gateway."'/>
    </network>
    <on_boot>true</on_boot>
    <vnic_profile id='bbabc471-667d-4221-bc8e-4ab30b3dcc34' />
   </nic>