I'm currently trying to add a calendar overlay to a custom SharePoint-Calendar using the Client Object Model. I've done this before, using the Server Object Model. See the Code sample below:
SPView targetView = calendarList.Views["SampleView"];
String XML = "<AggregationCalendars>" +
"<AggregationCalendar Id=\"{1873e3f2-1e8f-4c46-94fe-6aaf0bd89c1d}\" Type=\"SharePoint\" Name=\"Sample Aggregation\" Description=\"\" Color=\"5\" AlwaysShow=\"True\" CalendarUrl=\"/path/to/calendar/Sample Aggregation.aspx\">" +
"<Settings WebUrl=\"http://server/path/to/calendar\" ListId=\"{73ec9181-0bf1-4263-9387-905cc1ec6d38}\" ViewId=\"{814140ee-3291-45fb-b994-b6e22dbc8676}\" ListFormUrl=\"/path/to/calendar/DispForm.aspx\"/>" +
"</AggregationCalendar>" +
"</AggregationCalendars>";
targetView.CalendarSettings = XML;
targetView.Update();
Is there any (convenient) way to do this using the Client Object Model?