Note: Some customers have reported that not all USB flash drives are bootable. Some USB drives that have been tested and are known to be bootable include the Mushkin Flashkin, Transcend JetFlash, and Lexar Jumpdrive.
The trick is to create a network boot floppy with all the files you would need. Then, just follow the steps in the knowledgebase to make the USB storage device a bootable partition. After this is done, copy the files from the floppy disk to the USB storage device. Done!
For information on how to create a network boot floppy, please check out this knowledgebase:
DOS Ethernet Drivers for the Intel PRO/100 Adapters in PXI-8180 and PXI-8171 Series Controllers, the PXI-8211/2 boards, and VXI-770/870B Series Controllers
If you do not have a Windows 9x machine available to create a boot disk, you can get a Windows 9x boot disk from a third party supplier, such as bootdisk.com. Then you just have to copy the ethernet drivers onto the floppy to make it a network boot disk (remember you may need to change some ini files to reflect your network settings).