TeamCity - Encrypt connection strings?

Question

I fought with TeamCity and cannot succeed for this team. (It works fine by hand.) I tried a lot of things, and, surprisingly, Google didn't help much. All I'm trying to do is encrypt the connection strings in the web.config file after deployment.

cd C:\Windows\Microsoft.NET\Framework\v4.0.30319
ASPNET_REGIIS -pef "connectionStrings" "{mypath}"

Error: The configuration for the physical path '{mypath}' could not be opened.

I have it as the second build step after my publication as a type of creeping line on the command line.

I should also mention:

• Yes, I select the folder where web.config is located, and not the file itself.
• Yes, the path is correct, assuming that it should be on the server. (C: \ Inetpub \ MySite)
• Most importantly: I'm looking for a solution in TeamCity, and not in the manual or in the site code.

Thank!