If you are creating the data in VB.NET and then opening the report via code, it is easiest to use formulas. Just create two formulas in your report that return a dummy value. Put those on the report where they are supposed to be. Then when VB.NET creates the report object, override the formula values using the following line of code:
myReportDocument.DataDefinition.FormulaFields("xxx").Text="999"
This overrides the current formula value with the new one.