from MSDN article on the subject we can see that we create a TableHeaderRowthat conatins TableHeaderCells.

but they add the table header like this:

myTable.Row.AddAt(0, headerRow);

witch outputs the HTML:

<table id="Table1" ... > 
<tr> 
    <th scope="column" abbr="Col 1 Head">Column 1 Header</th>
    <th scope="column" abbr="Col 2 Head">Column 2 Header</th>
    <th scope="column" abbr="Col 3 Head">Column 3 Header</th> 
</tr>
<tr> 
    <td>(0,0)</td>
    <td>(0,1)</td>
    <td>(0,2)</td>
</tr>

...

and it should have <thead> and <tbody> (so it works seamless with tablesorter) :)

<table id="Table1" ... > 
<thead>
<tr> 
    <th scope="column" abbr="Col 1 Head">Column 1 Header</th>
    <th scope="column" abbr="Col 2 Head">Column 2 Header</th>
    <th scope="column" abbr="Col 3 Head">Column 3 Header</th> 
</tr>
</thead>
<tbody>
<tr> 
    <td>(0,0)</td>
    <td>(0,1)</td>
    <td>(0,2)</td>
</tr>
    ...
    </tbody>

the HTML aspx code is

<asp:Table ID="Table1" runat="server" />

How can I output the correct syntax?

Just as information, the GridViewcontrol has this builed in as we just need to set teh Accesbility and use the HeaderRow

gv.UseAccessibleHeader = true;
gv.HeaderRow.TableSection = TableRowSection.TableHeader;
gv.HeaderRow.CssClass = "myclass";

but the question is for the Table control.