Change The Log File Filter (SourceSwitch ) Values At Run Time?

I want to change the log file filtering at filtering at runtime. I am referring to the traceEventType in the following example.

My.Application.Log.WriteEntry(String.Format("{0:T} DeserilizeProperties", Now), _
TraceEventType.Verbose)

I have found the documentation that allows me to change it in the config file, but I need to do it at runtime. What I am trying to acheive is to allow a beta tester to turn on more detailed logging (according to the TraceEventType...) when encountering an issue in order to email me the log. And then switch back to less detail.TraceEventType.Information)

.Application.Log.WriteEntry(String.Format("{0:T} Send email", Now), TraceEventType.Information)