@BKlaus
put the export link from the plugin page in tpl_functions.php at line 239 like:
print '<a href="' . exportlink($ID, 'pdf') . '"><img src="' . DOKU_BASE . 'lib/images/fileicons/pdf.png" alt="PDF Export" /></a>' . DOKU_LF;
@mou
put the same line in main.php on line 118.
You cannot remove the textpart of the icons without altering a DW core function (tpl_action()) or implementing your own.