WHAT IS VISTEX USED FOR?

The SAP Incentive Administration application by Vistex supports a variety of incentive agreements and programs u2013 from simplest to most complex. SAP Incentive Administration integrates seamlessly with your SAP software to provide robust administration, analysis, and reporting capabilities. This powerful application enables you to efficiently manage commissions and other incentive programs. You can set targets and quotas u2013 and monitor actual results against your budget. 

You may visit these links for further details.

http://www.vistex.com/

http://www.sap.com/solutions/solutionextensions/incentives/index.epx

Source: What is Vistex used for?