Front brake - trapped air

[GPZ1100ABS]

Last winter I did the front callipers with cleaning, new seals etc. 
During this process I inadvertently got some air into one the brake 
hoses. I bled the system using a compressor connected sucking device but 
the brake lever has since felt 'spongy' - not hard the way it was 
before. It hasn't got any worse, but it sure hasn't got any better 
either, so I've spent a couple of evenings trying to fix it. Again I 
have used the compressor and sucked almost a liter of new brake fluid 
through the system, first through one of the bleed valves, then the 
other. This did not make any difference at all. Then I did it the old 
way - which is also described in the ABS supplement - by squeezing the 
brake lever-opening the bleed valve-closing the bleed valve-releasing 
the brake lever repeatedly (my hand is partly paralysed today:-\ ). I 
had a plastic hose attached to the bleed valve and saw a couple of tiny 
air bubbles during the process, but I'm still not satisfied. There's 
gotta be some trapped air in there somewhere. The supplement says 'tap 
the brake hoses lightly', but other than that it just says that bleeding 
an ABS bike takes longer time and requires more patience. I have flushed 
the system with almost two liters of new brake fluid now - there can't 
possibly be that much fluid in the system? During both processes I had 
my wife top up the brake fluid reservoir continuously, so I'm sure that 
it is not new air. Furthermore the processes were done quite quickly so 
I don't think a bubble could have remained floating in the system.

I have come to the point where I don't know what to do next - except 
turn it over to the dealer and ask them to do it. Before I do that - has 
anyone tried this? And has THE trick about how to get the last air 
bubble out of the system?

Many thanks in advance:-)

Ped
'96 "Black Stealth" GPZ (ABS)
Denmark