Calling QueueUpdateProject method in OnSaving Event

Hi,

I'm trying to make changes to custom fields of Task level in OnSave server side event handler. After making custom field updates in Project Data Set, calling  QueueUpdateProjectmethod and it was failing because the user who checked out the plan is different and the user who is executing the code(service account). 

Any impersonation technic or anyother way that would help to call QueueUpdateProjectin onSaving event?

Help is appreciated.

Thanks, Ram