CPP13 — Value Box Mapping

Summary: This may be a naive question, but it seems like the C++ mapping
for value boxes is incomplete. As far as I can tell, the specification
defines the mapping for the following types:

basic types, enum, objref, string, wstring, struct, union, sequence, array, fixed, any

But what about the types that have not been mentioned?

value, value box, TypeCode, Principal, native, except

If these types aren"t allowed, does the specification say that somewhere?