Cisco VPN :: ASA5520 - SSL Password Change / Notification

Has any one got a working setup for SSL VPN users in regards to notification about password is going to expire and then providing the VPN user the opportunity to change password during the VPN login process, involving ASA5520 - ACS Radius server - Active Directory
 
Our VPN users are connecting with Cisco Any Connect VPN Client V.2.5.3046 to a ASA5520 running 8.4(1), all user validation is handled via Radius though a Cisco ACS 5.2 server, which in turn validates the users up against MS Active Directory.
 
For the relevant connection profile on the ASA, the options Advanced / General/ Password Management / Enable password management has been selected together with the Notify user 14 days prior to password expiration, as mentioned its connecting to a Cisco ACS Radius server with MSCHAPv2 enabled on both the ASA and ACS.
 
On the ACS server under users and Identity Stores > External Identity Stores > Active Directory we have a successful bind to the AD, the values End User Authentication Settings > Enable password change has been selected.
 
Just to make sure the password notification function is working in the first place I change the ASA5520 AAA Server group to use LDAP instead of Radius and configured a direct path towards one of our domain controllers, sure enough when the user logged in he got a notification about the password would expire in xx days and then provided with a option to change the password right away or just connect with the current password.
 
The thing is I don’t want to just use LDAP for VPN authentication, I have quite a expensive setup on the ACS servers with unique ACL's for various group of employees and especially for external consultants, I also use the ACS for customization for webpage and resources when Web VPN is used.
 
Can it really be so that password expiration notification only works using LDAP, and if this is really the case, is there any way to configure Dual Authentication, so I could first validate the user against LDAP and next against the ACS??
 
(Side note: I tried to configure the ASA to use LDAP as normal Authentication and then the ACS as Authorization, but it failed, first off because the ASA started to use PAP/ASCII against the ACS and even if I allowed that, it seemed like the ASA wasn’t parsing the users password onwards, with the result that ACS failed and the user account ended up getting locked out in the AD).