SecurityRules .Net inheritance between assemblies MarshalByRefObject

Hello,

I've got 2 assemblies (A and B) and 1 console application.

The console application creates an app domain with a restrictive permission set.

Assembly A defines a class cA that inherits from MarshalByRefObject.

Assembly B defines a class cB that inherits from cA.

The console app tries to create an instance of cB, but it throws an exception due to Inheritance security rules violated.

All assemblies use the SecurityRules(SecurityRuleSet.Level2).

I tried to apply the SecurityCritical attribute over cB, but it still throw an exception.

Anyone have a solution for this ?

I would like to keep the Level 2 security rule set.

Thanks