[Pharo-project] NativeBoost question

Hey! I have a struct something like this: struct { const char * attribute; int size; int datatype; } ...and I am trying something like this to match an NBExternalStructure: fieldsDesc ^#( String attribute; int size; int datatype; ) ...or even this: ^#( NBExternalString attribute; int size; int datatype; ) All these give me some DNU (nil) for #asAJOperand when emitting code. The only one that works is when I use NBExternalAddress as can be seen in action in NBTestStructure2. Is this by design or am I simply an early adopter and support for String etc isn't there yet? regards, Göran