After a previous comment, i realized the problem with the change of password in expired accounts. So, new try
Using the usual tools, you can wrap the code to do the password change in a .wsc (windows scripting component) file, register it, add to a com+ application running under the apropiated credentials (Administrator in your case) and instantiate the component from your asp code to do the password change.
That way the component will run under the needed credentials, and password will be stored inside com+ configuration.