follow that guide from "Installing Ralink firmware from an offline Raspberry Pi (dpkg)" down, but replace the firmware with the z1211 all deb firmware
i could only get it to work as an offline install,
here is the link to the firmware too for the v4000 use the all.deb one
http://ftp.uk.debian.org/debian/pool/no ... -firmware/
also make sure that your pi is connected to a usb proper "power supply", or a "high power outlet" on your pc, that is what is causing the other problems with the wifi adapter, ie there is not enough power going into the pi to power the wifi.
this should work if you follow the guide, make sure you do the usbcore part, that is what made it all work for me.
btw i started with a clean sd image just to make sure that anything else that i had done messing about was not interfering with the install.