changing default route

[OxY]

hi!

i have a little irregular problem with default route..
here are the details:

have two interfaces with the same ip, em0 connected to another server with crosslink, 
em1 is the public, can be reached from the internet connected to a switch.

em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=b<RXCSUM,TXCSUM,VLAN_MTU>
        inet 195.38.96.13 netmask 0xffffffc0 broadcast 195.38.96.127
        ether 00:13:d4:46:ae:91
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=b<RXCSUM,TXCSUM,VLAN_MTU>
        inet 195.38.96.13 netmask 0xffffffc0 broadcast 195.38.96.127
        ether 00:0e:0c:a2:ac:42
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

in rc.conf i have:
defaultrouter="195.38.96.65"
ifconfig_em0="inet 195.38.96.89 netmask 255.255.255.192"
ifconfig_em1="inet 195.38.96.89 netmask 255.255.255.192"

with these the OS puts the default route to em0, however i want to communicate with the world on em1 and
use em0 to connect to the other server on lan..

default            gateway. UGS         0  8065787    em0   <----need em1 here

i can't change ip, it must be the same on both interfaces..
how can i change the interface for defaultroute?

thank you for help!