I see these are pages created by the Data Assist wizard, not the security assist wizard.
On the update page, make the following changes:
Edit the server validations behavior, remove the Required validation for the password and edit the EL validation for the password to allow blank entry
then edit the update record server behavior, for the password column, change the binding code froM
<?php echo ((isset($_POST["UserPassword"]))?WA_MD5Encryption($_POST["UserPassword"]):""); ?>
to:
<?php echo ((($_POST["UserPassword"] != ""))?WA_MD5Encryption($_POST["UserPassword"]):$row_WADAusers["UserPassword"]); ?>
remove the spry validation for the password field:
var UserPassword_Spry = new Spry.Widget.ValidationPassword("UserPassword_Spry", { minChars:6, isRequired:true , validateOn:["blur"]});
edit the password form element and remove the initial value.
this way, the password will only get updated if a new one is entered.