If you are doing anything with Rights Management Server (RMS) you really need to have a look at this paper and the associated reference application. 

This white paper provides architecture and design guidance for building an Information Rights Management (IRM)-aware application using Microsoft Active Directory Rights Management Services (AD RMS). It presents a number of application patterns as well as best practices that you can use for developing IRM-aware applications. It covers basic consumer and publish scenarios as well as complex federated scenarios that make use of Active Directory Federations Services (AD FS). The IRM Application Patterns Reference Implementation (http://go.microsoft.com/fwlink/?LinkId=149875) available on MSDN implements the patterns discussed within this article.

Download the paper here