Answering my own question just in case somebody else needs to do the same:
Using version 2.05+
in application\controllers\PrintanswersController.php, line 103 change this:
$sOutput = CHtml::form(array("printanswers/view/surveyid/{$iSurveyID}/printableexport/pdf"), 'post')
."<center><input type='submit' value='".$clang->gT("PDF export")."'id=\"exportbutton\"/><input type='hidden' name='printableexport' /></center></form>";
to this:
if (app()->getConfig("usepdfexport") == 0) {
$sOutput = "";
} else {
$sOutput = CHtml::form(array("printanswers/view/surveyid/{$iSurveyID}/printableexport/pdf"), 'post')
."<center><input type='submit' value='".$clang->gT("PDF export")."'id=\"exportbutton\"/><input type='hidden' name='printableexport' /></center></form>";
};
I hope this helps someone