Application to use Local Excel/Outool etv.

Hi!
We have a ERP system that through functions exports data to a temporary file and opens it in Excel.
Since the application is published as a remote app and not through desktop we want to have the app use the clients Excel to open the file but we cannot find out how to.

Same with Outlook, the program spawns a request to Outlook (New message) and attaches a file.
MAILTO works but the reference to outlook.exe does not.
Anyone had a similar usecase?