SharePoint Online 2010 MSCOCAF warning about SPDiagnostics.TraceWrite but the SPDiagnostics class is not allowed in sandboxed solutions

Dear All

I normally develop on premise and am new to SharePoint Online development so sorry if this is a bit of a 'newbie' question

When I run MSOCAF through my code it tells me to put SPDiagnostics  Write Trace calls in at the beginning and end of my event receivers.

"Please add SPDiagnostics WriteTrace call at start and end of Function
SomeProject.ListEventReceiver.FieldAdded(Microsoft.SharePoint.SPListEventProperties)"

In the Microsoft SharePoint Online Custom Solution document it says to put logging at the start and end of event receivers also.

Looking at the documentation (MSDN) SPDiagnosticsService is not available in SharePoint 2010 sandboxed solutions:

http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.administration.spdiagnosticsservice(v=office.14).aspx

Also on MSDN it says to use proxy objects in a kind of hybrid way, which is something I cannot do within my present environment.

The warning is still shown though with MSOCAF and I would like to know if there is a way round this? The MSOCAF version I am using is for SharePoint 2010, and I just through it was strange that it is asking me to use a class that I am not allowed to use (not allowed in sandbox).

Many thanks in advance if anyone can shed any light on this one.

Alan Howard