To accomplish this, you would need to write out your radio group dynamically using a loop. You would have to find the value that was selected and put in the code for it to be selected.
To add the selected code you would just add selected into the tag.
The unselected button looks like this:
<td width="70"> <p> <label>
<input name="TShirt" type="radio" id="XS" value="XS" />
XS</label></p></td>
The selected button would look like this:
<td width="70"> <p> <label>
<input name="TShirt" type="radio" id="XS" value="XS" selected/>
XS</label></p></td>
