How to create an azure vmss with public ipv6 address.

Here is the problem I meet. 
I have already deployed an azure vmss with azure load balancer. the load balancer has an public ipv4 address. 
I want to update this azure vmss, once scale up new vmss instance, each instance should have its own public ipv6 address. so that the data traffic will not forwarded by the load balancer.