Can you embed structs from different packages?

[maxless]

I have structs defined in a different package that are referenced from the main one. In this case msgpack generator ignores them, stating so:

main_test.go: TestRequest: service.RequestHeader: ignored.

Service package:

package service

type RequestHeader struct {
   FieldA int `msg:"fielda"`
}

main package:

type TestRequest struct {
  service.RequestHeader `msg:",flatten"`
  Data struct {
      Test int `msg:"test"`
  } `msg:"data"`
}

If flatten tag is commented out, the message is different:

main_test.go: TestRequest: unresolved identifier: service.RequestHeader