This wasn't a lucky day. Because of trouble with the Buffalo-Piratebox-version I pushed the development of the piratebox scripts. While testing, I recognized, that the packages I mentioned to built INTO the ramdisk version, are not built in.
So I decied to flash my RB411u now. After erasing the nand via bootloader-menu (Serial-Connection required), I started with the whole thing.
python -m SimpleHTTPSever 80
ifconfig br-lan:0 192.168.0.5 netmask 255.255.255.0
Then it totally crashed with an out-of-memory error and I have no idea why.