Hi all,
Right after posting this I had an idea.
Configuring a segment port profile can be done when creating the segment port. If you click Add Segment Port then it's possible to assign a Segment Profile to an individual port.
But that's no good for vSphere VMs that are assigned a port by changing the network configuration in vCenter. So as fas as I can tell at the moment it's not possible to modify the profile for a port that was auto-assigned through ESXi.
Rob