One can already with 2.0-alpha-4 use archetypes from secured (https) repositories, not by specifying archetypeCatalog URL parameter, but by specifying archetypeRepository URL parameter. It is undocumented at the moment, but after 2.0-alpha-4 code analysis, I found that archetype plugin, if archetypeRepository parameter is provided, internally creates ArchetypeRepository instance with URL equal to archetypeRepository parameter value, and with id equal to "%artifactId%-repo" where %artifactId% is the value of archetypeArtifactId parameter. To provide credentials one has to adjust either global or user settings.xml file, by adding server definition with id equal to this calculated artifact repository id, and with appropriate credentials.
Problem is that if one was to use N different artifacts (with different artifactId) from same repository, one would have to define N server definitions in settings.xml which is not nice at all.
To fix this problem, I've extended archetype plugin with additional archetypeRepositoryId parameter which can be passed together with archetypeRepository (URL) parameter. If archetypeRepositoryId is configured together with archetypeRepository then plugin will construct and use ArchetypeRepository with id equal to archetypeRepositoryId parameter value. If only archetypeRepository is configured, plugin will work as before (so change is backwards compatible), setting ArchetypeRepository id to "%artifactId%-repo".
Attached is proposed patch ( org.apache.maven.archetype.maven-archetype-
ARCHETYPE-220.patch ) with fix described above. No new unit nor integration tests are included - existing ones all pass.
Documentation should be updated too with appropriate example.