Cross Database Activation Security

I have two databases Basket_ODS and Intelligence_ODS.

I created a user in the Basket_ODS and Intelligence_ODS databases as follows:

USE Basket_ods

GO

CREATE MASTER KEY ENCRYPTION BY PASSWORD = '*******'

CREATE USER BasketServiceUser WITHOUT LOGIN

ALTER AUTHORIZATION ON SERVICE::[Order Send] TO BasketServiceUser

GRANT CONTROL ON SERVICE::[Order Send]

TO BasketServiceUser

CREATE CERTIFICATE BasketServiceCertPriv

AUTHORIZATION BasketServiceUser

WITH SUBJECT = 'ForBasketService'

BACKUP CERTIFICATE BasketServiceCertPriv

TO FILE = 'BasketServiceCertPub'

In the other database...

I created the following:

USE Intelligence_ODS

GO

CREATE MASTER KEY ENCRYPTION BY PASSWORD = '************

USE Intelligence_ODS

GO

CREATE USER BasketServiceUser WITHOUT LOGIN

CREATE CERTIFICATE BasketServiceCertPub

AUTHORIZATION BasketServiceUser

FROM FILE = 'BasketServiceCertPub'

My Queue is in BASKET_ODS and is set up as:

ALTER QUEUE ODS.[Order Process Queue] WITH

ACTIVATION (

STATUS = ON,

PROCEDURE_NAME = ODS.ProcessOrderQueue,

MAX_QUEUE_READERS = 4,

EXECUTE AS 'BasketServiceUser'

)

I have performed the following grants in Basket_ODS

grant execute on ODS.ProcessOrderQueue to BasketServiceUser

ProcessOrderQueue calls [ODS].[MoveOrderTotals_Core] in the Intelligence_ODS database.

grant execute on [ODS].[MoveOrderTotals_Core] to BasketServiceUser

ProcessOrderQueue proc is set as follows:

ALTER procedure [ODS].[ProcessOrderQueue]

WITH EXECUTE AS 'BasketServiceUser'

[ODS].[MoveOrderTotals_Core] is set up as follows:

when I run ProcessOrderQueue I get an error message:

ALTER procedure [ODS].[MoveOrderTotals_Core](@Orderid uniqueidentifier)

with execute as 'BasketServiceUser'

I just don't understand when I run ProcessOrderQueue I get the following error message (when database trust is turned off)

The server principal "sa" is not able to access the database "Intelligence_ODS" under the current security context.

Can you help me figure out what I'm doing wrong. I've spent so much time on this security stuff. Is there another way to do this that is more straight forward without using database trust?