Suppose that BankSoft has a library of C or C++ functions and wants to plug these functions in to the Integration Service. In particular, the library contains BankSoft’s own implementation of the FV function, called PreExistingFV. The general method for doing this is the same for both COM and Informatica external procedures. A similar solution is available in Visual Basic. You need only make calls to preexisting Visual Basic functions or to methods on objects that are accessible to Visual Basic.