Submit Button - Members Form

Hello I am trying add a submit button to my form using the <button> I don't seem to be achieving things very well.

Original code:

<perch:input <button type="submit" value="Sign me up!" class="btn"></button>

Out put seems to ignore the <button> tag?

 <input class="btn" value="Sign me up!" type="submit" /><input type="hidden" name="cms-form" value="" /></button>

help appreciated