You cannot. In KIM 3.5, we use Sesame 2, which has a different model for remote access, incompatible with the old web interface.
In the mean time, you can use the JMX management for running SeRQL / SPARQL queries using in particular the com.ontotext.kim.client.SemanticRepositoryMgmt management bean. Use jconsole or VisualVM with the MBeans plugin as a JMX client. Both are located in the bin/ folder of your JDK.