I've tried this one with the drivers from "extra3615_v0.11_test"
bootloader ds3615_6.2
and DSM_DS3615xs_25426.pat
The inital boot completes, but after installing DSM_DS3615xs_25426.pat it stops at GRUB bootloder (showing GRUB GRUB _)
No chance to interrupt GRUB (to try to change some linux-boot commands or something)
EDIT:
The Problem was booting from the HDD/RAID
After choosing the USB-Thumbdrive as default it worked fine (havent read your instructions quiete well)