Raid 0 boot problem

[Oldtimmer]

First off Kubuntu 13.04 looks very nice and runs good from USB (Good Job).
raring-desktop-i386 installed on Hardware raid 0 (name br) (Bios raid, Fake raid) 13.04 found the raid 0 with no problem
So I did a manual partitioning and told it to install boot loader to /dev/mapper/asr_br.
But the install put the boot loader on my USB install drive instead of /dev/mapper/asr_br.
I had to install and run boot-repair to fix it.
Boot loader is now installed to /dev/mapper/asr_br and boots fine.
I do not know if this is a bug in the installer or if I did something wrong.


System

Dell Precision 670 Workstation
2 x Xeon(tm) 3.4GHz
SCSI Controller Adaptec AIC-7901A
2 x 15k 147GB SCSI HD's Hardware raid 0 (Bios raid, Fake raid)
2GB Ram
ATI 5450 Video card

Does anyone know what I might have done wrong during install.

[Oldtimmer]

I tried to install 13.04 using a DVD instead of USB flash drive.
I have 2 usable partitions

/dev/sda (first disk in raid)
/dev/mapper/asr_br (Raid 0)
/dev/mapper/asr_br1 ( / )
/dev/mapper/asr_br2 (swap)

Under manual partitioning I selected (/dev/mapper/asr_br1) for boot loader install but the installer tried to install the boot loader to /dev/sda anyway and install fails on grub install.
I installed and ran boot-repair to fix it.
Seems the installer is ignoring the boot loader install selection or does not see the raid partition.
Does anyone have any suggestions.