VBA to Sort Pivot Table (Specific Column)

Hey guys,

How can I sort a specific column in a Pivot Table using VBA? The name of the column will appear in cell E28 on Tab SEM1

When I record the macro, sorting a column looks roughly like this.

 ActiveSheet.PivotTables("PivotTable1").PivotFields("Category").AutoSort _
        xlDescending, "Sum of August - 2012", ActiveSheet.PivotTables("PivotTable1"). _
        PivotColumnAxis.PivotLines(4), 1

I want the "Sum of August - 2012" to be a variable which looks at cell E28

Thanks all! Love you <3!

Lucas