You should be able to create any type of chart.
The way that OfficeWriter SSRS integration works (and just the plain Template object for that matter), is that it takes all of your data and inserts it into your data markers. Then it finds references in your workbook that pointed to your data markers, and expands them to point to all of the new inserted data.
So really you can add any type of chart. You just have to make sure that the chart you create points to the data markers as the source data.
A data marker will correspond to a single series or to horizontal axis data. Then as the data is populated, the values in the series are populated.
On our reporting demo page there's a link at the bottom that says "View Report Template" that you can click on to download and Excel file that shows a variety of different charts pointing to data markers.