Querying an external index

Hi,

I have two separate, but related, sites. One of the sites I would like to promote on the other. One of the ways I'm going to promote it is by showing search results from the smaller site on the primary site.

I have created a separete IClient instance with:

IClient mySecondClient = new Client(serviceUrl, indexName);

When trying to access the results with GetResult I get a 401 Unauthorized error.
What configuration options are needed in order to query an external index? I can't find anything in the documentation about this.

Edit: Quite embarrasing but the 401 error was because of an incorrect serviceUrl and indexName. I get no errors now, but no results either. I try to get the results with filterForPublicSearch set to false.

Thanks!

/Niklas