Excluded object from search - object-type changes to 0

Hi,

Using the client COM-API, I'm giving in the object-type argument as follows:

var condition = new SearchCondition();
condition.Expression.SetStatusValueExpression(MFStatusType.MFStatusTypeObjectTypeID);
condition.ConditionType = MFConditionType.MFConditionTypeEqual;
condition.TypedValue.SetValue(MFDataType.MFDatatypeLookup, objectTypeID);
return condition;

The object-type I'm using (in this case: Category, object-type 141) is excluded from search within the advanced vault configuration. 

Executing the search, seems to result  in a list of document-objects (object-type 0).
The search is executed by calling:

vault.ObjectSearchOperations.SearchForObjectsByConditionsEx(searchConditions, MFSearchFlags.MFSearchFlagNone, true, maxResults);

I've fixed this now in the application, by an extra filter on the object-type (and so this results in 0 items). But actually I would expect no result at all?

And some follow-up questions, to know if there are ways to work around the setting to exclude objects from search.

Is there another way to get the full list of object-type 141 in this case? 
I also tested the REST-API, and for example this GET-call still gave results (but limited of cource):
https://{M-Files endpoint}/REST/objects/141

And could I retreive the full list by using the index-arguments and loop trough the results?
And is there a equivalent via the COM-API, or is this behavior only in the REST-API?

Thanks for any help in advance.

Kind regards,

Chris