[Link: universalremote.com]

Here is the pdf manual. Veiwsonic isn't listed. Get an MX-850 and load the codes into it then teach them to the URC-100. A lot of work but worth the $350 you will save. Maybe the new R-series has the code. They are cheaper and you needed to go by CC and check them out anyway right.
Just checked, the R5 is $40 at CC. It has the code for Veiwsonic (242). Maybe you can try that one in the URC-100. Or try the search programming feature, something is bound to work.