setting background theme for the newly added contact in outl

Question

      I am facing a problem in outlook using c#, My Issue is, I want to add a default theme to the contacts that are added newly,

so that i can differentiate with existed one. Here is the code that i have tried.

public void Addcontact_Click(Office.IRibbonControl control)

{

MessageBox.Show("Add Contact");

OutLook._Application outlookObj = new OutLook.Application();

OutLook.MAPIFolder fldContacts = (OutLook.MAPIFolder)outlookObj.Session.GetDefaultFolder(OutLook.OlDefaultFolders.olFolderContacts);

OutLook.ContactItem newContact = (OutLook.ContactItem)fldContacts.Items.Add(OutLook.OlItemType.olContactItem);

newContact.FirstName = "Sai";

newContact.LastName = "S";

newContact.Email1Address = "[email protected]";

newContact.Save();

}

#endregion

Any Help is appreciated,

Thanks in advance