Sharp changed things in the ROM, so that this worked in 2.x but not in 3.x
Still it shouldn't be that hard to create a script in /etc/rc.d/init.d which would bring up the wireless interface.
Or it _could_ be even easier. I see the file /etc/sysconfig/network which has NETWORKING=no
I haven't tried it, but setting that to yes, along with the rest of the networking info you require (IP address, gateway...) might work for you.
I hope this helps,
Craig...