Your best bet as I've mentioned before is to download the ISO for DSL. Once you launch the ISO from within the virtual machine, you can then use the running DSL environment to create the embedded installation unto your pen drive.
To create a virtual machine with Q, just create a new one within Q and it will ask you questions as to what type of computer you want to emulate (x86, x86-64, PPC, etc.). Once you've made the choice, tell it to boot from the ISO image you downloaded from the DSL site. Once all of that is set, start the virtual machine and it should begin to boot DSL. Once the X Windows session is up and running, access the menu for DSL and in the menu selections there should be one to create an installation unto the USB flash drive.