Problems with NegaFix

[halaja]

I'm using Silverfast 5.5 with an Epson Perfection 2400 Photo.
When scanning color negatives (properly exposed Fuji Superia 400), the scanned image shows quiet heavy posterization in the shadow areas, and deep tones (for example red hair). Scanning the same negative with Epson TWAIN doesn't cause this problem, the shadows are cleaner. For me it seems to be a gamma correction error.
My monitor is set to gamma 2.2 with adobe gamma.
The Silverfast settings are:
-Gamma gradation 1.8 - 2.2
-Color management OFF
(I have tried with CM On using the Epson 2400 profile supplied with Epson TWAIN, the results are similar)
-Photoshop working space sRGB

How can I solve the above mentioned problem?
What are the appropriate Color Management settings in Silverfast and Photoshop if I don't have an IT8 target and I want to get the best possible color accuracy? Should I use the color profile supplied by Epson?
I am confused with color management.

Thanks in advance

[LSI_Kratzenstein]

You should use the Epson profile for better results.

Please send a picture to kristian.kratzenstein@SilverFast.com , so I could see, where your problem is with the negafix. A screenshot would be the best.

kind regards