Why do I get this Error when mapping Entity to View Object?

Why do I get this Error when mapping Entity to View Object?

Hi.
By mistake I created a VO before creating the Entity so when I got the mapping dialog I omitted it. Then I created the Entity in the ERM and went back to the BOM to map said Entity in my VO. but when selecting the Data Object Type button I find the following error:


I easily achieved it by deleting the VO and recreating it, fixing this time to map it through the dialog.
Is there any other way other than to delete and recreate the VO?
How could I do it?