Date picker's calendar icon not opening the date picker

Hello,

I got this date picker which works fine:
<input id="ReturnDate" name="ReturnDate" type="text" value="" class="form-control tleft past-enabled" pattern=".{1,}">

But when I add the calendar icon next to it, clicking it does not open the date picker. This is the code:
<div class="input-group-append">
<div class="input-group-text"><i class="icon-calendar2" ></i></div>
</div>

I need the button to open the date picker.
(btw, I have two date pickers on the page, so it has to open the specific one.)

This is the full code:
<div class="input-group ltr">
<input id="ReturnDate" name="ReturnDate" type="text" value="" class="form-control tleft past-enabled" pattern=".{1,}">
<div class="input-group-append">
<div class="input-group-text"><i class="icon-calendar2"></i>
</div>
</div>

Please help.

Thanks!

anyone here?

Here: http://new.autoeurope.co.il/

Thanks!

Still waiting...