I have a blades chasis HP C7000. In my chasis I have 4 ethernet switches in the Interconnect bays (and 2 fiber channel brocade). I have ESX 3.5 U4 installed on 2 blades, and each blade have 4 NICs. I configure a virtual switch for my virtual machines traffic, I create 2 port group with VLAN 6 and VLAN 7 and I assign 2 NICs to this vswitch. Each NIC is connected to a different switch on the chasis and I configure nic teaming and traffic shapping in this vswitch.
I have each switch (c7000 switch) connected to a port in my pshysical switch. I configure this port as trunk mode but I cant comunicate from my virtual machines to my phisical servers.
On the other hand, I have another ESX installed on a HP DL380, connected to a port on my physical switch, configured equal than the ports for the C7000 connectios, and it´s work correctly.