Hi Manuel,
To fix the missing artifact problem you need to add http://repository.jboss.org/nexus/content/groups/public/ to you settings.xml. You can find a full set of instruction on the Maven Getting Started page.
To answer you first question, I am thinking that it may need to be a branch or you only build it for the latest version of Spring.
2nd question - most of us use github. It is free and can post your code there. Then others can review and test it.
thanks,
Joshua