Hi Jitendra,
you can create external views for any HANA view, i.e. attribute views, analytical views, and calculation views.
The display of external views via SE16 could lead to "GROUP BY" issues, therefore the colleagues have restricted the display of external views (on analytical views) in SE16. Yet, I agree, the error message could be enhanced to give you an information why that is the case 
.
Cheers,
Jasmin