DSL not using Maven Proxy settings

We are getting an error downloading artifacts from the jetbrains repo on our TC server when it attempts to run DSL updates:

Failed to apply changes from VCS to project settings (revision 760f5df7d03bd73a5edbc3546d8241bf9b467cae): Failed to get DSL dependencies: Could not transfer artifact junit:junit:pom:4.12 from/to jetbrains-all (http://download.jetbrains.com/teamcity-repository): Connect to download.jetbrains.com:80 timed out. Please fix the errors in VCS and commit again.

We need a proxy on our server to reach the external Maven repo, and have added the Maven proxy configuration in mavenSettingsDsl.xml on the root project's Maven Settings page. The file is getting used, because if the XML is poorly formed we get an error, but the proxy is not used as we still get the same timeout error. I have tested the settings on a local workstation and they work, Maven attempts to download artifacts from the configured proxy.

Is there another way we are supposed to configure proxies for use with Maven artifacts references in the DSL? Note we have setup the proxy in the TC internal properties as well.