I want to search all res_users that belong to a certain res_company via xml-rpc. The test client is written in .net env. When i keep the search query simple like searching on the "login" field = 'login_name_x' this works fine.

            String[] condition = new String[] { "login", "=", "name_x" };
            ArrayList lstFilters = new ArrayList();
            lstFilters.Add(condition);
            Object[] resSearch = openERPproxy.search(dbname, userID, pwd,res.users",search", lstFilters.ToArray());

But i need to filter on de company_ids where a res_users records belongs to. So i tried following filter as i know there are res_users in company_id 3

            String[] condition = new String[] { "company_ids", "=", "3" };

But this is not a working solution because it returns nothing?!

What is the correct approach to get xml-rpc do search filter on the many2xxx fields?