Hi again,
after rebooting and loading my modules (and starting hcid, sdpd and 
rfcomm, the latter probably unnecessary but I'm erring on the side of 
caution?), I run:
sudo hcidump -w dumpdata

but just get:

HCIDump - HCI packet analyzer ver 1.5
Can't attach to device hci0. No such device(19)

and it exits without writing anything to the file.

and "hciconfig -a" exits silently.

then I run hid2hci anyway, it prints:
Switching device 05ac:1000 to HCI mode was successful

and then I can do hcidump -w dumpdata
which gives me to stdout:
HCIDump - HCI packet analyzer ver 1.5
device: hci0 snap_len: 1028 filter: 0xffffffff

I had wait a while before it wrote anything to the file.
Then I waited a bit more, and it wrote a bit more. This is normal.
I've attached the file.

 > I don't know what kind of module this is. Please run "hcidump -w <file>"
 > before running "hciconfig -a" and send us the dump. Maybe we have a big
 > endian problem here. What bluez-utils version do you have installed?


2.4-6 from Debian sid, as well as utils2 from bluez cvs. hciconfig comes 
from that cvs checkout (though I have two version in my path, the cvs 
version takes precedence, while hcidump comes out of Edds bluez-hcidump 
package, version 1.5-2 for debian sid.


> Reboot your machine and show me this file before you run hid2hci.

I'm sorry, but it wasn't possible since hcidump wouldn't write one, as 
described above.