Read data for Instance 0 and instance 1 on FX Legato app

Please see the test requirement LW.070 on confluence page

Copy LW.070 info here ===

An application Ax is installed on the module and allows to read one data S1 (Type String), one data S2 (Type Int), one data S3 (type Float) , one data S4 (Type Boolean).
An application model for the Ax is linked to the system.
A Dataset R1 linked to the application Ax is already created (see Configure activity) and allows to read the data S1, S2, S3 and S4 for the Instance 0 and for the Instance 1
The details page of the system is displayed.

U selects “More” > “Retrieve data”
U selects R1 and launches the action.

Expected results:
A ‘Retrieve data’ operation is created and retrieved by the device at its next connection to AirVantage server.
Once operation is done and success, S1, S2, S3 and S4 are updated in the application configuration page of the application Ax for each instance 0 and 1
Values can be read also in the last connection line displayed in the TimeLine page

I have tried the sample app ‘assetData’ on ALMS server and FX30 CatM (and Cat1) device, and ‘retrieve data’ operation works, and read the data for instance 0 successfully, and cannot read data for 2nd instance.
How can I read the data S1,S2, S3, S4 for instance 0 and instance 1? What shall I specify in the Legato application?