VBO user entity views

Hola, actualmente estoy realizando un pequeño sistema donde me encuentro con unas dificultades, ahora les digo de que va, cree un tipo de contenido con la siguientes características

Evento (Tipo de Contenido)
->Titulo del evento (text)
->Personajes (Field Collections, ilimitado)
--->Descripción del personaje (Text)
--->Agregar Artista (Field buttton)
--->Artistas (Field Collections, ilimitado)
----->Participante (user)
----->Estatus del Participante (Term reference)
----->Observaciones (Text)

Hi, all- I am fairly new to Drupal and very new to rules, and I am facing a problem I am certain others have faced. I need a way to update a user field on multiple nodes in one submission, on Drupal 7 using the latest version of Views Batch Operations ("VBO"). VBO can easily do this for the "author" property - that appears to be a built-in drupal action. But if I use Rules to assign a user, I don't get the nice User field drop down list with a choice of all the users like the Change Author action does. Instead I get the "Set Parameter window with various data selectors.