Netflow traffic from TMG2010

Hi,

We are using Solarwinds NPM and NTA.We have one TMG 2010 server as a proxy in our network.All traffic to the internet is passing through this server.I need to get netflow traffic in TMG server for knowing the details of users who is accessing internet.I know TMG will not support netflow.Please give me a solution for this.

Regards,

Rejeesh