Set Interval of Years in Microsoft.WindowsMobile.PocketOutlook.AppointmentRecurrence

Hi
i want to set the interval of years in the object of type Microsoft.WindowsMobile.PocketOutlook.AppointmentRecurrence
for eg i have coded like this :
Microsoft.WindowsMobile.PocketOutlook.obj = new Microsoft.WindowsMobile.PocketOutlook.AppointmentRecurrence();
obj.RecurrenceType = "Yearly";
obj.Interval =2 ;
It is going error.
i know we cant set the interval in Yearly events.it works ok with daily or monthly.
But i have to set the interval with yearly. for eg event after each 2 years.
Any one have idea Help me!!!