I picked this up on another post:
UPDATE USING DATEPICKER MUST BE DONE MANUALLY
GRAB THE STUFF IN THE HEAD OF THE INSERT PAGE
What the WA update looks like BEFORE
<input type="text" name="DocDate" id="DocDate" value="<?php echo(str_replace('"', '"', $row_WADAdownloads['DocDate'])); ?>" size="32" />
What the WA update looks like AFTER
<input id="datepicker_1" name="DocDate" type="text" value="<?php echo($row_WADAdownloads['DocDate']); ?>" />
It worked for me