More a note to self than a serious blog post (haven't got the time to do screen shots and stuff).
When creating BAM views in Excel, you can copy the initial PivotTable that is generated to create multiple predefined 'views'. To copy the PivotTable select it (go to the edge until you get a solid arrow cursor) then Copy it (Ctrl+C), select a free cell well below the existing PivotTable and Paste (Ctrl+V). Right-click in the Pivot Table and select Table Options... to give it a name. This Name must be unique across the workbook. Otherwise the PivotTable will not be linked to a cube when exported (although it all seems to work in excel) and your view will be missing from the Aggregations node in the BAM Portal navigation pane.