vmxnet3 interfaces cannot enable auto negotiation

I'm using a customized linux guest system (kernel 2.6.36, no vmware tools installed), wanted to switch from e1000 to vmxnet3 for better performance, but found auto-negotiation is off by default and cannot be enabled, is this correct for vmxnet3? Will this cause problem if working with lower speed peers?

Interface name            port1
Link encap                Ethernet
HWaddr                    00:0C:29:09:9F:33
inet addr                 192.168.96.101
Bcast                     192.168.96.255
Mask                      255.255.255.0
Status                    up
MTU                       1500
Metric                    1
RX packets                4684
errors                    0
droppet                   0
overruns                  0
frame                     0
TX packets                49
errors                    0
droppet                   0
overruns                  0
carrier                   0
collisions                0
txqueuelen                1000
RX bytes                  328720 (321.0K Bytes)
TX bytes                  3456 (3.3K Bytes)
Supported ports           [ TP ]
Supported link modes      1000baseT/Full 10000baseT/Full
Supports auto-negotiation No
Advertised link modes     Not reported
Advertised auto-negotiation    No
Speed                     10000Mb/s
Duplex                    Full
Port                      Twisted Pair
Physic Address            0
Transceiver               internal
Auto-negotiation          off

Thanks!

Alan