As far as I can tell from the guide, the only copy protection mechanism for the Ovi Store is OMA DRM 1.0 Forward Lock. Nokia documented  that OMA DRM 1.0 by itself is not enough to protect native S60 applications, because the DRM protects only the SISX file, not the installed application. That same document provides a solution to the problem, but the Ovi Publishing Guide doesn't provide enough information to implement that solution.
In particular, the Nokia-proposed solution requires bundling an additional license file in the DRM wrapper, modifying the DRM wrapper, and then modifying the application to manually check the rights. However, in the Ovi Store, the application developer does not control the DRM wrapper. Please provide an explanation and/or example of how to implement this protection.