Ubuntu 14.04 "Trusty Tahr" Minimal CD on pen drive?

hello, forgive my poor English please...

i'm in trouble about Ubuntu 14.04 "Trusty Tahr" Minimal CD on PEN DRIVE.

i've Ubuntu 14.04 on computer and a mini.iso file downloaded from the "Ubuntu Documentation" page section 64-bit PC (amd64, x86_64) ver 14.04 (64 bit ).

- it work perfectly using Brasero program, it read the iso file correctly and create a bootable cd/dvd, it is fine.

- i've some trouble using usb-creator program.. it do not read correctly the iso file container... i can't make a pendrive bootable ...
.while open the iso file using archive manager it extract the file contained
.while open the iso file using image mounter it mount a new device with lable "firmware" but empty files

i'd like to know how make a pendrive bootable using minimal CD from image 32 and 64 bits
tanks regards