Embedded runtime is always used for dependency resolution

eclipse luna配置maven installtion時，會提示這句。
意思大概是：eclipse本身運行一些任務時使用內置的，你的項目若是想用外置的，須要顯示指定："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:

<prerequisites>
    <maven>>=2.2.1</maven>
</prerequisites>