Bridge issue - maybe a Skeinforge issue?

I have an issue with printing the following test object: [www.thingiverse.com]
When I observe the printing process, the bridges (even the longest) start to print almost perfect, the perimeters don't fall down / sag. However the problem starts when the printer starts with the infill / solid layer. Here it does a zig-zag pattern. See . No good comes out of this and this part of the extrusion basically just falls down. But subsequent layers where the bridges are realized using straight lines, things look nice. But this first 'layer' of the bridge is not working at all. See and .

So it seems that the printer is very much capable of this kind of bridges, but the slicer (Skeinforge) ruins it. Unfortunately I'm not really an expert of the different settings of Skeinforge to find out how I can influnce this, so I mostly use Print-O-Matic in ReplicatorG with some overrides. I attach the gcode (I used gcode.ws to visualize what happens exactly).
Some parameters:
0.27mm layer height
0.4mm nozzle
1.82mm diameter
235C blue ABS
Feedrate 80 mm/sec, Travel feedrate: 150mm/sec
Number of extra shells: 0 (based on the description from the thingiverse thing)
Infill: 2% (I also tried 5%, also tried to change the inflill pattern)

Any idea what I can do to successfully print these bridges? Somehow it seems that the first layer / infill pattern doesn't consider the fact that it's actually printing mid air over a bridge?

This part is made to push your printer to its limits so you can find and tweak issues to work at their optimum. So it is not surprising to have difficulties with it. On these bridges I think the only way that the infill would be supported is if it is joined to the perimeter all along the way. You could try increasing the value of the skeinforge setting Fill, Infill Perimeter Overlap to help join the fill to the perimeters better (try .20). Maybe you could also try slowing your infill speed a little to help it join the perimeter? Just my best guesses-

Thanks a lot for the ideas, I will try them out!
What is suprising to me and also visible on the photos, that somehow the second such bridge only "bends", but the perimeter layer it uses seems to be using straight, long lines, instead of the zigzag pattern I have shown on my gcode layer screenshot. So it seems that sometimes Skeinforge gets it right, or maybe just a coincidenence?
That bend / sagging is probably just due to temperature. But the first and third layer issue seems to be something else.
But I will try this Infill Perimeter Overlap setting... Could work.

Thanks again!

I think there is a skeinforge setting for bridge infill in direction of bridge.

Thanks, this parameter (infill direction) indeed did the trick! Now there's only a minor sagging, but that is probably due to temperature.