Ok so if your using 4.0 custom workflows and not 3.0 callouts, you should add a workflow assembly, and use the Context service and executing context of your workflow to pull the values from the new note.
See the example below on how to access a record using the context service and the ID of your current context of execution (that should be your note)
/// <summary>
/// The Execute method is called by the workflow runtime to execute an activity.
/// </summary>
/// <param name="executionContext"> The context for the activity</param>
/// <returns></returns>
protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
{
// Get the context service.
IContextService contextService = (IContextService)executionContext.GetService(typeof(IContextService));
IWorkflowContext context = contextService.Context;
// Use the context service to create an instance of CrmService.
ICrmService crmService = context.CreateCrmService(true);
BusinessEntity newNote = GetNote(crmService, context.PrimaryEntityId);
string noteAttrib;
noteAttrib = newNote.Properties.Contains("AnnotationId") ? ((Lookup)newNote.Properties["annotationid"]).name.ToString() : null;
return ActivityExecutionStatus.Closed;
}
GetNotes method would be a standard query for notes by Id through a CRM service call,
here is an example slightly modified from MSDN to return a note:
private BusinessEntity getNote(ICrmService service, guid noteid)
{
// Create the column set object that indicates the fields to be retrieved.
ColumnSet cols = new ColumnSet();
// Set the columns to retrieve, you can use allColumns but its good practice to specify:
cols.Attributes = new string [] {"name"};
// Create the target object for the request.
TargetRetrieveAnnotation target = new TargetRetrieveAnnotation();
// Set the properties of the target object.
// EntityId is the GUID of the record being retrieved.
target.EntityId = noteid;
// Create the request object.
RetrieveRequest retrieve = new RetrieveRequest();
// Set the properties of the request object.
retrieve.Target = target;
retrieve.ColumnSet = cols;
// Execute the request.
RetrieveResponse retrieved = (RetrieveResponse)service.Execute(retrieve);
return RetrieveResponse;
}