When searching for a vendor in the rich Verification Station, the vendor is found with as little as 3 characters entered. However, on Web Verification Station, the vendor is found with at least 5 characters entered.
There are certain differences between web stations and rich stations. Some functions are not available at web stations at all, while some other features use different mechanisms that are more optimized for the web station interface running inside the browser. Data set search is one of such features.
Please note that it is not that the vendor cannot be found at all. It may just be required to type in more characters to get the required record in suggestions.