In the latest 2.5 version , when I use the shortcode {CLEARALL} in pstpl files this is translated in
<button type="submit" id="clearall" value="clearall" name="clearall" class="clearall button btn btn-default btn-lg col-xs-4 hidden" data-confirmedby="confirm-clearall" title="Cette action doit être confirmée.">Sortir et effacer vos réponses</button>
BUT as you can see, it is always mentioned with the class hidden which means we can NEVER display it The only way I found is to directly write the code removing the hidden class in order to be display this button ie not to use the keyword .
You should be able to overrule the .hidden style by inserting your placeholder in a <div> element with a distinct class - say, "button-div" - and then target that with something in template.css like this (untested):
Sorry about thet yes it is about CLEARALL ( save feature not activated in this survey) but I suppose the same will occur for SAVE and SAVE_LINKS keyword