When I run dmassage, the resulting modifications prevent using raid.

        dmassage -f /bsd | config -e -o /nbsd /bsd

If I understand correctly, the softraid device is showing in the dmesg, 
so it shouldn't get removed by dmassage.

excerpt from diff of dmesg's after dmassage and before dmassaging>

$ diff dmesg.dmassage dmesg 
...
279,280c280,282
< root device vscsi not configured
< root device softraid not configured
---
quoted text
> vscsi0 at root
> scsibus0 at vscsi0: 256 targets
> softraid0 at root
294a297,299
quoted text
> scsibus1 at softraid0: 1 targets
> sd0 at scsibus1 targ 0 lun 0: <OPENBSD, SR RAID 0, 003> SCSI2 0/direct 
fixed
quoted text
> sd0: 7331MB, 512 bytes/sec, 15014913 sec total


This is on current i386

/Lars