Daniel,
The Azure WebApp service provides support for FTP publishing, however it gives you access to the entire publishing area and does not support specifying access to a specific folder.
What you are advised to do in this scenario is to create two WebApp services:
- YourAppPrincipal.azurewebsites.net
- YourTerceirizada.azurewebsites.net
And then you organize your addresses with subdomains.
- www.dominioprincipal.com.br
- third-party.domain.com
Now, to meet something like dominioprincipal.com.br/solucaoterceirizada
, only if the outsourcer sends you the sources, you can merge both applications and upload in a single hosting.
However, because I'm outsourced, I prefer the first scenario, so the outsourced solution - which, theoretically, you do not have control like the way it was developed - will run under a host independent of the primary one. So if she has a problem and falls, she will not knock down next to the main app. And vice versa.