PBI dataset as an SSRS data source

Hi,

We have a PowerBI dataset that we want to use as a data source in SSRS

Our data source (Microsoft SQL Server Analysis Services) connection string currently looks like this:

Data Source="powerbi://api.powerbi.com/v1.0/myorg/MyWorkspaceName";Initial Catalog="MyReport"

I can use query designer to configure my SSRS dataset, using the MyReport model. However when I try to run the SSRS report, I get the following error regardless of authentication settings:
Authentication failed: User ID and Password are required when user interface is not available

When I configure the connection string like this:

Data Source="powerbi://api.powerbi.com/v1.0/myorg/MyWorkspaceName";Initial Catalog="MyReport";Userid="mypbilogin";Password="mypassword"

I cannot access the model, and get the following error both when I try to run the report and configure the dataset via query designer:

The remote server returned an error: (403) Forbidden

I'm able to access and refresh the PBI report using the same login.

Any ideas? Is there another component that requires permissions?

Thanks in advance