XFRM device not automatically created?

In my /etc/config/network I have an entry for an XFRM device AND (which I didn't know I needed to install) I have the xfrm.sh script installed from network packages.

What am I missing that I still have to do a manual creation of the XFRM device? once the device is UP additional features are automatically added like MTU which is under the same config interface and routing.