Hi,
i solved the problem.
It looks like i screwed my nvram settings, with too much different Firmwares.
I tried DD-WRT and Freewrt before i installed Openwrt (kamikaze) and with every firmware i made some changes with nvram tool for testing purposes.
After resetting nvram settings and reflshing with openwrt, it works quickly like i wanted.
"mtd -r erase nvram"
"cd /tmp"
"wget http://downloads.openwrt.org/kamikaze/7.06/brcm-2.4/openwrt-brcm-2.4-squashfs.trx"
"mtd -e linux -r write openwrt-brcm-2.4-squashfs.trx linux"
> reboot
change /etc/config/wireless with your settings
change /etc/config/network
#### WAN configuration
config interface wan
option ifname "wl0"
option proto dhcp
ifup wan; wifi
done