How update only "Numbers" settings of QA Checker settings of file-based project in SDL Studio 2011

 Hi,

I need to update only "Numbers" settings of QA Checker settings of file-based project. i do it with a next code:

ISettingsBundle settings = project.GetSettings(project.GetProjectInfo().TargetLanguages[0]);
Sdl.Verification.QAChecker.Settings.NumbersSettings nums = new NumbersSettings();

nums.CheckDates = false;
nums.CheckNumbers = false;
nums.CheckMeasurements = false;
nums.CheckTimes = false;
nums.SaveToSettingsBundle(settings, "QAVerificationSettings");
project.UpdateSettings(settings);

But it reset another qa-settings too. How can I update only part of settings?

And where i can find description for Sdl.Verification.QAChecker.Settings ?