Hi dodo-dk, I just tried your updated package, thanks to you and thanks again to Seba.
But with is spk, on a real ds415+ NAS, the NAS... crashes !
EDIT //
Never mind, just installed the updated kernel package you provided on your blog, it works now
(but notice that you don't have to reboot the nas, in the package manager the option "start"/"stop" works well)