This is a known issue which has been fixed in the latest internal build
of Telerik Reporting Q3 2013 (126.96.36.1995). Thus, our suggestion is to upgrade to the latest internal build and check if the issue still persists.
You can interact with reports created in the standalone report designer after you deserialize them in your application. You may find useful the following articles on the topic:
Still in order to advise you more accurately please elaborate on your exact scenario that requires to interact with the report definition in code.
New HTML5/JS REPORT VIEWER with MOBILE AND TOUCH SUPPORT available in Telerik Reporting Q3 2013! Get the new Reporting version from your account or download a trial.