DSM 7.1 Need Help using Reverse Proxy Custom Headers

[Ltek]

I need the proxy to convert http://192.168.2.60 into http://192.168.2.60/api

I do not want anything passed to the app unless it uses /api (secure comms) since without the /api this old crappy app is not secure.

I cannot find any docs or example of exactly what to enter into the proxy's customer header fields.

thx for the help!