UAC Timeout ?!? disable, increase interval or how get informations

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I start a process per:

ProcessStartInf o si = new ProcessStartInf o("Task.exe") ;
si.Verb = "runas";
Process p = Process.Start(s i);

On Execution the UAC dialog will be displayed.
If the user selects nothing for two minutes, this dialog will be closed.
The win32exception error code is -2147467259 on this timeout AND on user
“cancel” selection.

Is the any way to know -what is happened (cancel or timeout)?
Or could I disable this timeout anyway?