Juan,
Looking at your bug report, it looks like you might be able to work around this problem by telling subversion to checkout the parent of the directory containing the parent pom. In other words, Vulcan is only getting the source code for the parent pom, so the modules don't get checked out.
Then, configure the maven plugin to use parent/pom.xml.
You would need to do this by manually changing the configuration instead of using the import feature.
Hope that helps,
Chris