OWA Publishing in Two layer DMZ

Hi,

My company has Exchange 2010 infrastructure.As of now OWA and Outlook is working perfectly in internal network.Now we want to Publish OWA to internet users.What is the best way to publish the OWA in below scanario.We have two layer DMZ configured and Citrix Netscalers are being used for Load balancing.Also currently there is no direct connection to Firwall from Internal Network.

We want to consider Reverse Proxy option but not sure how to go forward.

any help is really appricated.

Thanks,

Messenger

With Regards Crew,