Problem getting SSO to Sharepoint 2013 to work after DUO push authentication.

Okay i have now managed to solve my problem, it was easier than i thought. The VPE flow is picture below:

There is a Pre Logon variable assign where we set the original password as a variable:

After the Radius Authentication Duo we have the post logon where we set the logon username in the form Domain\username and then pull in the original password variable we set before:

The final part is the SSO Agent which is the the default collecting information from the default variables:

I hope this proves useful to others. /Craig