After looking through several opensource mail server programs my friend pointed zimbra out to me. After running the example it was clear to me : Zimbra does what the other mail servers only promise !
Because I needed lvm2 and mdadm software raid together with some other kernel options I learned (by experience) gentoo was the easiest way to get it working the way I wanted. Since gentoo isn't a common choice for system administrators I installed zimbra in an unbuntu chroot and it running like a dream.

thus : T.H.A.N.K.S. Zimbra we love you