Embedded runtime is always used for dependency resolution

eclipse luna配置maven installtion时，会提示这句。
意思大概是：eclipse自己运行一些任务时使用内置的，你的项目如果想用外置的，需要显示指定："Run As > maven install"
`Translating to English, it means that Eclipse will continue to employ its internal Maven instance in order to perform some tasks. When you "Run As > maven install" it will run your pom.xml script employing the external Maven instance you specified but when Eclipse performs some of its internal stuff, it will continue to use the embedded Maven instance, whatever version it is.

(edited) As far as I know, when you install M2Eclipse you are implicitly defining which "internal Maven instance" you will have, which is exactly that one packaged by the plugin. In the plugin configuration, you can add external Maven instances by telling where they are installed.
If you are using a recent m2eclipse version, you can try this too:

    >=2.2.1