Hi Roland,
That should work. While I don't use the /ini_file parameter for end users (I push out a registry setting instead), I do use for my "admin" connection when I want to modify the shared saplogon.ini. The only differences I can see in my usage and what you posted is 1) I put the parameter in lower-case, so perhaps it's case-sensitive (though I wouldn't have thought so), and 2) I'm using SAPGUI 7.30 instead of 7.40.
I can't recall whether this came up in your earlier question, but are you using NWBC 5.0 in conjunction with SAPGUI 7.40? Or just the SAPGUI?
Regards,
Matt