Thoose controls are in a datagrid
you have to go to the selectcommandname of the datagrid
and do the following.

in the html
tag datagrid1 for exemple

selectcommandname="doselect"

in the code behind
'you have to build a datagrid selectcommand and call it doselect
dim yourbutton as button
yourbutton=e.item.findcontrol("the button'name in the datagrid") '
'later
yourbutton.caption="what ever you want"