[jhautz]

when you soldered them did you solder to the tabs or directly t the cell? The a123 is more sensitive to heat than MiMH cells and I read that if you overheat them by soldering direct to the seal in the cell will be damaged and they will vent. Could this possibly be your problem? You could probably overheat a cell by keeping the heat on the tab too long as well if your not carefull.