After set master mode can't see essid from other laptop

I have wireless usb with prism2 chipset

iwconfig wlan0 mode master
iwconfig wlan0 essid test

Setting master mode doesn't complain anything
with essid set, i can't see essid from other laptop
am i missing something?

and I also have device with prism54 chipset(usb)
on the web it says it support ap mode
when I typed

iwconfig wlan0 mode master

it complains and it can't be done
anyone knows how to set p54usb to master mode?

anyone knows wireless usb adapter that works with ap mode
in linux?