For the time being you can set the types through the kendoWidget:
<telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
<script>
function pageLoad() {
var chart = $find('<%=RadHtmlChart1.ClientID%>');
chart._chartObject.options.series[0].type = "verticalLine";
chart.repaint();
}
</script>
</telerik:RadCodeBlock>
<telerik:RadHtmlChart runat="server" ID="RadHtmlChart1" Width="600px" Height="400px">
<PlotArea>
<Series>
<telerik:LineSeries Name="Product 1">
<SeriesItems>
<telerik:CategorySeriesItem Y="15000" />
<telerik:CategorySeriesItem Y="23000" />
<telerik:CategorySeriesItem Y="10000" />
</SeriesItems>
</telerik:LineSeries>
</Series>
<XAxis>
<Items>
<telerik:AxisItem LabelText="1" />
<telerik:AxisItem LabelText="2" />
<telerik:AxisItem LabelText="3" />
</Items>
</XAxis>
</PlotArea>
<ChartTitle Text="Product sales for 2011">
</ChartTitle>
<Legend>
<Appearance Position="Bottom" />
</Legend>
</telerik:RadHtmlChart>