Well, I DO want to obfuscate them, but I do not want the types themselves renamed - they are loaded at runtime via reflection. In other words, all private and internal fields/properties/methods of a type should be obfuscated, but the type name, its public methods, and the namespace name it resides under should remain unchanged.
If these types is public types you can use ObfuscationOptions.Members = KeepSerialization predefine in the assembly obfuscation settings of Spices.Project.
In this case classes that probably is used in serialization and their's public members will untouchable, but private/internal members will obfuscated.