Webtrends Analytics 9 Adminstration Guide, November 2012
Place the WT.svl parameter on every page where multiple links lead to the same page.
Assign each link a unique value. For example if three different links on each page go to the same target page, you would assign each link a unique value as shown in the following example:
SmartView uses WT.svl to assign the appropriate measure values to individual links.