ifconfig and route problem.

[DrumFire]

Hi,

this is my configuration:

rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=8<VLAN_MTU>
        inet 192.168.100.1 netmask 0xffffff00 broadcast 192.168.100.255
        ether 00:30:84:9e:9d:26
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

and this is my default route 

default            192.168.100.254      UGS         0        0    rl0

If I write something of this:

# ifconfig rl0 $ip (where ip can be also 192.168.100.1), my default
route is deleted, cut off server for my net.

There's a way to avoid ifconfig delete my default route when I modify 
a ipaddress?