ASP.NET Identity requires dbo permission?

I have an existing application database.  I created an ASP.NET MVC5 project in VS2013 and ran the project to create the ASP.NET Identity tables in the auto-configured localdb database.  I synchronized the database definitions (Red-Gate) and added the dbo.AspXX tables, keys, relationships, etc. to my existing database.
I changed the connection string to use an "application" login with read and write permissions on most schemas.  When attempting to register, the ASP.NET app throws a "CREATE TABLE permission denied in database " error.  I changed the connection strin to allow Integrated Security, and all is well.  Reset back to a user with realistic web application permissions and the create table error returns (even though the tables not only exist but also contain data).
What's up?  I didn't have this trouble with ASP.NET Memebership and I can't imagine MS is ignoring best practices (although I have so ...