Hi,
Function Module RSDRI_INFOPROV_READ only works for the following supported InfoProviders: DSO, InfoCube and MultiProvider. Please also refer to the on-line documentation of the Function Module.
So it won't work in your constellation. I suggest to look for a different setup where e.g. you could use of of the suported InfoProviders.
Moreover, please try to make the setup a bit more standardized, more transparent and easier to understand. A Virtual Cube is meant for particular cases (e.g. to access the latest data in the source system, low volumes only), certainly not for data staging. I would be in favor of a more classic data staging scenario.
Best regards,
Sander