Globalization and Cultures

We got all Windows cultures with the Command:
CultureInfo[] allCultures = CultureInfo.GetCultures(CultureTypes.SpecificCultures);     
The same list is in the
Language Property of the System.Windows.Forms.Form.
Is it possible to add own elements into this list?
Maye be, wee need "customer1-DE", "customer2-DE"...