Error 'Couldn't load the data for this visual' w/ Measures from DirectQuery for SAP BW BEX Query

[Blackjack]

Greetings, 

I'm having trouble loading my report measures when using DirectQuery for SAP BW on Power BI cloud service.
Here is the error message:

"Couldn't load the data for this visual

MdxScript(Model) (5, 42) Cannot find data source '' in function 'EXTERNALEXPRESSION'.
Please try again later or contact support. If you contact support, please provide these details.

Activity IDba46f5a8-2e0e-40a5-99c8-3849f2baaaab

Request IDec00dc39-9f95-5c3c-e6ee-5e4e95fb06aa

Correlation ID0c939e55-b820-03e1-3024-c14d1d51cb13

Version13.0.1781.239"

Some facts: 

 - I'm loading dimensions and measures (key figures) from SAP BW Query perfectly well in Power BI Desktop;

- The issue happens only with Measures on the Power Bi Service after publishing the report;

- Dimensions and Hierarchies are loading seamlessly on Power BI service;  
- The Data Gateway is up and running;
- I've tried to convert the measures into currency format, but to no avail;

Has anyone run into the same problem using DirectQuery (beta) and Data Gateway connecting to a SAP BW Query?

Thanks!