1. Scanner redirection does not create a device on your virtual desktop that matches the name of the actual scanner. It creates a generic scanner in Device Manager called VMWare Virtual WIA Scanner (or VMWare Virtual TWAIN Scanner I am assuming). For us this stinks because the image capture software our client uses (Vertex by Jack Henry), has a prepopulated list of scanners you can select. So if we plug in a Canon-CR50 and select Canon CR50/80 in the application, it does not recognize that this scanner is attached to the virtual desktop.
2. You must install a TWAIN or WIA driver on your thin client. If you can't find a TWAIN or WIA driver, you are out of luck. For teller check image scanners, we have found no TWAIN or WIA drivers for the TellerScan TS-230, TS-240, or the Canon CR-55. We have found a TWAIN driver for the Canon CR-50 (from the Canon Europe site no less), but issue #1 above means we are out of luck.