fwe and fwip not working with fwohci0: <VIA Fire II (VT6306)>

Dear lists,

since I couldn't get the speed I need with GbE em cards I bought a pair of 
firewire 1394a cards and a 6-to-6-Cable.
I tried fwe, could ping the other host and also transfer very little files via 
ftp, but as soon as I try to shovel a view hundred kByte files the connection 
stalles. Of course, same with NFS, there I can't transfer any file.
Then I compiled a kernel with ipfw but it's exactly the same.

Also one machine hangs sometimes at boot when the cable is connected to both 
cards and the other machine is running, with the following lines:

fwohci0: <VIA Fire II (VT6306)> port 0xd800-0xd87f mem 0xe2041000-0xe20417ff 
irq 5 at device 10.0 on pci0
fwohci0: OHCI version 1.0 (ROM=1)
fwohci0: No. of Isochronous channels is 4.
fwohci0: EUI64 00:11:06:00:00:00:75:86
fwohci0: Phy 1394a available S400, 3 ports.
fwohci0: Link S400, max_rec 2048 bytes.
firewire0: <IEEE1394(FireWire) bus> on fwohci0
fwe0: <Ethernet over FireWire> on firewire0
if_fwe0: Fake Ethernet address: 02:11:06:00:75:86
fwe0: Ethernet address: 02:11:06:00:75:86
fwe0: if_start running deferred for Giant
sbp0: <SBP-2/SCSI over FireWire> on firewire0
fwohci0: Initiate bus reset
fwohci0: node_id=0xc800ffc1, gen=1, CYCLEMASTER mode
firewire0: 2 nodes, maxhop <= 1, cable IRM = 1 (me)
firewire0: bus manager 1 (me)
[...]
firewire0: New S400 device ID:0011060000007587
firewire0: split transaction timeout dst=0xffc0 tl=0x7 state=3
firewire0: bus_explore node=0 addr=0x40c resp=60 retry=1

Then nothing happens but the system isn't frozen since "numlock" key is 
toggling the keyboard LED.

For a verbose boot or a full dmesg please see 
http://www.schmalzbauer.de/document.php?id=22

I have no idea where to start finding the real problem.

Has anybody out there ever been able to use tcp/ip over the VIA VT6306 
firewire link?

Thanks,

-Harry