[web2py] UUID as Primary Key?

[Brian M]

Is there anyway to use the DAL with a database that used UUIDs as the
primary key in a few tables?  The setup below just gives errors
because registered_user.UserId (the id field) isn't an integer as
expected (ValueError: invalid literal for int() with base 10:
'6BBC2607-1B6A-4C8A-BBD4-8566754CFA20')

#Table: registered_user
#Stores user profiles
#Yeah I know this isn't web2py's Auth table - I'm integrating with
a .NET app.
db.define_table("registered_user",
    Field("UserId","id", length=64, default=uuid.uuid4()),
    Field("first_name",  "string", notnull=True),
    Field("last_name", "string", notnull=True),
    Field("street", "string", notnull=True),
    Field("city", "string", notnull=True),
    Field("state", "string", notnull=True),
    Field("zip", "string", notnull=True),
    Field("lastUpdatedDate", "datetime", default=datetime.now(),
notnull=False),
    migrate = do_migration
    )

#Table: group_leader
#Stores the leader(s) of each group
db.define_table("group_leader",
    Field("group_leader_id", "id"),
    Field("group_id",db.volunteer_group),
    Field("UserId",db.registered_user),
    migrate = do_migration
    )

Thanks in advance.
~Brian