Mapping WebDAV ContentClass, OutlookMessageClass and other properties to EWS Managed API

I'm working on a migration from WebDAV to EWS Managed API in Exchange 2010 and i'm having some problems with property mappings.

In WebDAV I had a custom .Net wrapper and with it i created a where condition like this:

Where w = new Where();
w.Add(new WhereCondition(Properties.ContentClass, Enums.ComparisonOperatorsEnum.NotEquals, "urn:content-classes:message"));
w.Add(new WhereCondition(Properties.OutlookMessageClass, Enums.ComparisonOperatorsEnum.Like, "IPM.Schedule.Meeting.Resp.%"));

The wrapper just creates the proper WebDAV search SQL statement under the covers.

The Properties.ContentClass equals to DAV:contentclass in the WebDAV XML schema
and i've kind of mapped it to Item.ItemClass in EWS. At least I hope this maps to it.

Properties.OutlookMessageClass equals to http://schemas.microsoft.com/exchange/outlookmessageclass in the WebDAV XML schema.
But I haven't found any EWS properties that woulp map to that one.

Is there a known mapping somewhere?

Thanx, Mladen

Have fun!