arcehtype:create-from-project not honoring -s parameter in integration-test phase

I am running maven within a firewall and have a mirror of the Maven
repository within the corporate firewall. When specifying a proxy and using Maven Central, or just about any mirror outside the corporate firewall, I get build errors, so I need to use our internal mirror. The build is faster this way as well. I have a settings.xml file which contains information on our mirror and without a proxy set so we only use the internal mirror. When running the maven-archtype-plugin by using:

mvn -X -s /path/to/my/settings.xml archetype:create-from-project

I see this debug statement

[DEBUG] Added basic integration test
[INFO] Scanning for projects...

then maven attempts to download these two files:

org/apache/maven/archetype/*archetype-packaging/2.2/*
archetype-packaging-2.2.pom
org/apache/maven/archetype/*archetype-packaging/2.2/*
archetype-packaging-2.2.jar

However, the download is from Maven Central outside the firewall, which
causes the build to fail. It appears that the settings parameter isn't
being propagated to the integration-test phase. How can I get the
integration-test phase to use the settings.xml file I've specified?