Securid authentication for IKE client

[Mittal Harshwardhan-A18990 <harshmittal@motorola.com>]

Hi all,

I am currently working on a VPN client and wants to get the client authenticated using RSA Securid ACE card.
I have all required information ( userid, passcode, acecard value).

IKE phase 1 is complete with some default group-id and password.

I am using Cisco 5000 series concentrator as a server which is not under my conrol, 
but I have my ace-card and laptop (windows and linux) client (provided by Cisco) configured for the server,
and I am able to estblish VPN session both from linux and windows.

My question is what is the packet format in which I can send my ace-card credentials to the cisco server
to get my client authenticated.
What is the protocol, I think Cisco client is sending this info in form of IKE informational exchange.
but as the packet is encrypted using ISAKMPD SA I am unable to find out the packet format.

thanks in anticipation

Regards,
Harsh