Ok, found out myself:
First
rmmod btmrvl_sdio (if loaded for some reason)
Then start
/etc/init.d/bluetooth start
Then
modprobe btmrvl_sdio
with the original 2.6.38.8 module.
Thanks to the /root/init_setup.sh script...

Voila, hcitool dev works on 2.6.38.8.
(I'm using 2.6.38.8 because there isn't a working linux-vserver patch for 2.6.39.x)