[Surface Raider]

I am playing an OM uboat campaign and at the start of the career I have to select the difficulty level of the game. After selecting this option and starting and saving my mission I can go to the main menu game options screen. I noticed that main window game options sets the difficulty to an appropriate level set by OM. I can then adjust the parameters to increase or decrease the realism and save it as customized, but when playing the missions it seems that the pre-set OM game settings will override the customized game settings at the SH4 main menu. Is there a way to play this game using the customized settings instead of the OM preset difficulty levels? I am using OM 705/720.