I know what you mean, this took me a bit to figure out myself :)
The syntax is ifconfig le1 inet [ip address] broadcast [broadcast address]
netmask [netmask address]

	I have my system set to multicast and usually set the broadcast
address to the ip netnum.255 and netmask to 255.255.255.0 Let me know if
it doesn't work out.

	Chris