normally one uses DCOM. Some more detailed steps can be found here.
BUT: you need to create the Automation Server differently. You need to specify the host on which MATLAB is installed, configured for DCOM and should be used. I am not sure if LabView is able to do that.
However what definetly works is using the local MATLAB together with the Script Node to start the DCOM MATLAB from there. So LabView < - > Local MATLAB < - > Remote MATLAB