FreeBSD 5.3-BETA6 nuked DFBSD disklabel

[Johannes Hofmann]

In order to try the ipw driver on FreeBSD, I wanted to install FreeBSD
5.3-BETA6 on my second slice. But the installer nuked my DragonFly BSD
disklabel for slice 1 even though I instructed the installer to leave the
MBR alone (I am not sure whether it really did...).
I even reproduced the problem after restoring my original DragonFly
installation :-)
Is this a known issue?

 Johannes