if you do a 'show conn' you should see the connection id.
Then do a 'show np 1 me-stat "-c "'
There you should get a line with :
EncapsID:ver : 19:0
Then do a 'show arp' and check the entry whose encap column matches the encapid found previously.
You could also do a 'show serverfarm' and see which rserver has the current counter at 1 if you are working with 1 connection at a time.
Gilles.