Permission for Google Maps in manifest fails at deployment

Hey everybody,

Since I want to display a map in my app, I followed Xamarin's guide regarding MAPS Api. When I type all the permissions in the AndroidManifest and build the application, no problem. But when I want to launch the app, it fails and I get this error :

Deployment failed because of an internal error: Unexpected install output:
pkg: /data/local/tmp/my.package-Signed.apk
Failure [INSTALL_PARSE_FAILED_MANIFEST_MALFORMED]

I've found that the permission that causes this to happen is this one :

<permission android:name="my.package.permission.MAPS_RECEIVE" android:protectionLevel="signature" />

But I don't see what's wrong with it. If it makes any difference, I'm not launching the app on an emulator but on a device (Nexus 5).