wyse xenith Citrix USB Printing/invalid sessionconfig VUSB

After attempting to get XenDesktop/XenApp printing working using some degree of universal print driver on my new XenApp farm, I ran into an issue with assigning the sessionconfig line in the xen.ini file. Specifically, when I insert the following line….

SessionConfig=all mapdisks=no VUSB_DISKS=yes VUSB_AUDIO=yes VUSB_VIDEO=yes VUSB_PRINTER=yes

….I get a message in the event log on the Wyse Xenith saying…

Invalid SESSIONCONFIG parameter: VUSB_DISKS
Invalid SESSIONCONFIG parameter: VUSB_AUDIO
Invalid SESSIONCONFIG parameter: VUSB_VIDEO
Invalid SESSIONCONFIG parameter: VUSB_PRINTER

I am very new to this and just (today) got to the point where I have my xen.ini configuration file to download as well as using the firmware file that is included in the Citrix XenDesktop Wyse ‘addon’ (with much thanks to this site, which I also found today). So I’m thinking it may have to do with the fact that I’m running the default (which I think is 1.0.0_34) firmware on the device.

So, two questions. Is this accurate, and have people had success on newer versions of XenDesktop with USB printing?

And second, how do I get newer versions of Firmware for my Wyse Xenith?