Hi Tino and "Weldcome"
If you could elaborate more on the welding parameters; Current, Voltage, wire feed speed, type of flux, etc. Also the type of steel, thickness joint configuration and anything else besides what you already mentioned that would enable many of the participants of this forum to help you find a solution to your dilemma. Btw, did you contact the folks in Hanover, PA about your problem because they're usually the "go-to" guys for ESAB in the US.
I'm not that familiar with the process variant your working with although I've seen it applied successfully on a couple of occasions so, I apologize for not being more helpful. Without the above mentioned data, it's not going to be easy for someone here that really wants to help out. ;)
I look foward to your response. ;)
Respectfully,
Henry